diff --git a/vendor/golang.org/x/tools/LICENSE b/vendor/golang.org/x/tools/LICENSE
deleted file mode 100644
index 6a66aea..0000000
--- a/vendor/golang.org/x/tools/LICENSE
+++ /dev/null
@@ -1,27 +0,0 @@
-Copyright (c) 2009 The Go Authors. All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-   * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-   * Neither the name of Google Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/golang.org/x/tools/PATENTS b/vendor/golang.org/x/tools/PATENTS
deleted file mode 100644
index 7330990..0000000
--- a/vendor/golang.org/x/tools/PATENTS
+++ /dev/null
@@ -1,22 +0,0 @@
-Additional IP Rights Grant (Patents)
-
-"This implementation" means the copyrightable works distributed by
-Google as part of the Go project.
-
-Google hereby grants to You a perpetual, worldwide, non-exclusive,
-no-charge, royalty-free, irrevocable (except as stated in this section)
-patent license to make, have made, use, offer to sell, sell, import,
-transfer and otherwise run, modify and propagate the contents of this
-implementation of Go, where such license applies only to those patent
-claims, both currently owned or controlled by Google and acquired in
-the future, licensable by Google that are necessarily infringed by this
-implementation of Go.  This grant does not include claims that would be
-infringed only as a consequence of further modification of this
-implementation.  If you or your agent or exclusive licensee institute or
-order or agree to the institution of patent litigation against any
-entity (including a cross-claim or counterclaim in a lawsuit) alleging
-that this implementation of Go or any code incorporated within this
-implementation of Go constitutes direct or contributory patent
-infringement, or inducement of patent infringement, then any patent
-rights granted to you under this License for this implementation of Go
-shall terminate as of the date such litigation is filed.
diff --git a/vendor/golang.org/x/tools/README.md b/vendor/golang.org/x/tools/README.md
deleted file mode 100644
index 20be9e1..0000000
--- a/vendor/golang.org/x/tools/README.md
+++ /dev/null
@@ -1,27 +0,0 @@
-# Go Tools
-
-This subrepository holds the source for various packages and tools that support
-the Go programming language.
-
-Some of the tools, `godoc` and `vet` for example, are included in binary Go
-distributions.
-
-Others, including the Go `guru` and the test coverage tool, can be fetched with
-`go get`.
-
-Packages include a type-checker for Go and an implementation of the
-Static Single Assignment form (SSA) representation for Go programs.
-
-## Download/Install
-
-The easiest way to install is to run `go get -u golang.org/x/tools/...`. You can
-also manually git clone the repository to `$GOPATH/src/golang.org/x/tools`.
-
-## Report Issues / Send Patches
-
-This repository uses Gerrit for code changes. To learn how to submit changes to
-this repository, see https://golang.org/doc/contribute.html.
-
-The main issue tracker for the tools repository is located at
-https://github.com/golang/go/issues. Prefix your issue with "x/tools/(your
-subdir):" in the subject line, so it is easy to find.
diff --git a/vendor/golang.org/x/tools/container/intsets/popcnt_amd64.go b/vendor/golang.org/x/tools/container/intsets/popcnt_amd64.go
deleted file mode 100644
index 99ea813..0000000
--- a/vendor/golang.org/x/tools/container/intsets/popcnt_amd64.go
+++ /dev/null
@@ -1,20 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build amd64,!appengine,!gccgo
-
-package intsets
-
-func popcnt(x word) int
-func havePOPCNT() bool
-
-var hasPOPCNT = havePOPCNT()
-
-// popcount returns the population count (number of set bits) of x.
-func popcount(x word) int {
-	if hasPOPCNT {
-		return popcnt(x)
-	}
-	return popcountTable(x) // faster than Hacker's Delight
-}
diff --git a/vendor/golang.org/x/tools/container/intsets/popcnt_amd64.s b/vendor/golang.org/x/tools/container/intsets/popcnt_amd64.s
deleted file mode 100644
index 05c3d6f..0000000
--- a/vendor/golang.org/x/tools/container/intsets/popcnt_amd64.s
+++ /dev/null
@@ -1,30 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build amd64,!appengine,!gccgo
-
-#include "textflag.h"
-
-// func havePOPCNT() bool
-TEXT ·havePOPCNT(SB),4,$0
-	MOVQ	$1, AX
-	CPUID
-	SHRQ	$23, CX
-	ANDQ	$1, CX
-	MOVB	CX, ret+0(FP)
-	RET
-
-// func popcnt(word) int
-TEXT ·popcnt(SB),NOSPLIT,$0-8
-	XORQ	AX, AX
-	MOVQ	x+0(FP), SI
-	// POPCNT (SI), AX is not recognized by Go assembler,
-	// so we assemble it ourselves.
-	BYTE	$0xf3
-	BYTE	$0x48
-	BYTE	$0x0f
-	BYTE	$0xb8
-	BYTE	$0xc6
-	MOVQ	AX, ret+8(FP)
-	RET
diff --git a/vendor/golang.org/x/tools/container/intsets/popcnt_gccgo.go b/vendor/golang.org/x/tools/container/intsets/popcnt_gccgo.go
deleted file mode 100644
index 82a8875..0000000
--- a/vendor/golang.org/x/tools/container/intsets/popcnt_gccgo.go
+++ /dev/null
@@ -1,9 +0,0 @@
-// Copyright 2015 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build gccgo
-
-package intsets
-
-func popcount(x word) int
diff --git a/vendor/golang.org/x/tools/container/intsets/popcnt_gccgo_c.c b/vendor/golang.org/x/tools/container/intsets/popcnt_gccgo_c.c
deleted file mode 100644
index 08abb32..0000000
--- a/vendor/golang.org/x/tools/container/intsets/popcnt_gccgo_c.c
+++ /dev/null
@@ -1,19 +0,0 @@
-// Copyright 2015 The Go Authors.  All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build gccgo
-
-#include <errno.h>
-#include <stdint.h>
-#include <unistd.h>
-
-#define _STRINGIFY2_(x) #x
-#define _STRINGIFY_(x) _STRINGIFY2_(x)
-#define GOSYM_PREFIX _STRINGIFY_(__USER_LABEL_PREFIX__)
-
-extern intptr_t popcount(uintptr_t x) __asm__(GOSYM_PREFIX GOPKGPATH ".popcount");
-
-intptr_t popcount(uintptr_t x) {
-	return __builtin_popcountl((unsigned long)(x));
-}
diff --git a/vendor/golang.org/x/tools/container/intsets/popcnt_generic.go b/vendor/golang.org/x/tools/container/intsets/popcnt_generic.go
deleted file mode 100644
index 3985a1d..0000000
--- a/vendor/golang.org/x/tools/container/intsets/popcnt_generic.go
+++ /dev/null
@@ -1,33 +0,0 @@
-// Copyright 2015 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// +build !amd64 appengine
-// +build !gccgo
-
-package intsets
-
-import "runtime"
-
-// We compared three algorithms---Hacker's Delight, table lookup,
-// and AMD64's SSE4.1 hardware POPCNT---on a 2.67GHz Xeon X5550.
-//
-// % GOARCH=amd64 go test -run=NONE -bench=Popcount
-// POPCNT               5.12 ns/op
-// Table                8.53 ns/op
-// HackersDelight       9.96 ns/op
-//
-// % GOARCH=386 go test -run=NONE -bench=Popcount
-// Table               10.4  ns/op
-// HackersDelight       5.23 ns/op
-//
-// (AMD64's ABM1 hardware supports ntz and nlz too,
-// but they aren't critical.)
-
-// popcount returns the population count (number of set bits) of x.
-func popcount(x word) int {
-	if runtime.GOARCH == "386" {
-		return popcountHD(uint32(x))
-	}
-	return popcountTable(x)
-}
diff --git a/vendor/golang.org/x/tools/container/intsets/sparse.go b/vendor/golang.org/x/tools/container/intsets/sparse.go
deleted file mode 100644
index 5db01c1..0000000
--- a/vendor/golang.org/x/tools/container/intsets/sparse.go
+++ /dev/null
@@ -1,1091 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-// Package intsets provides Sparse, a compact and fast representation
-// for sparse sets of int values.
-//
-// The time complexity of the operations Len, Insert, Remove and Has
-// is in O(n) but in practice those methods are faster and more
-// space-efficient than equivalent operations on sets based on the Go
-// map type.  The IsEmpty, Min, Max, Clear and TakeMin operations
-// require constant time.
-//
-package intsets // import "golang.org/x/tools/container/intsets"
-
-// TODO(adonovan):
-// - Add InsertAll(...int), RemoveAll(...int)
-// - Add 'bool changed' results for {Intersection,Difference}With too.
-//
-// TODO(adonovan): implement Dense, a dense bit vector with a similar API.
-// The space usage would be proportional to Max(), not Len(), and the
-// implementation would be based upon big.Int.
-//
-// TODO(adonovan): opt: make UnionWith and Difference faster.
-// These are the hot-spots for go/pointer.
-
-import (
-	"bytes"
-	"fmt"
-)
-
-// A Sparse is a set of int values.
-// Sparse operations (even queries) are not concurrency-safe.
-//
-// The zero value for Sparse is a valid empty set.
-//
-// Sparse sets must be copied using the Copy method, not by assigning
-// a Sparse value.
-//
-type Sparse struct {
-	// An uninitialized Sparse represents an empty set.
-	// An empty set may also be represented by
-	//  root.next == root.prev == &root.
-	//
-	// The root is always the block with the smallest offset.
-	// It can be empty, but only if it is the only block; in that case, offset is
-	// MaxInt (which is not a valid offset).
-	root block
-}
-
-type word uintptr
-
-const (
-	_m            = ^word(0)
-	bitsPerWord   = 8 << (_m>>8&1 + _m>>16&1 + _m>>32&1)
-	bitsPerBlock  = 256 // optimal value for go/pointer solver performance
-	wordsPerBlock = bitsPerBlock / bitsPerWord
-)
-
-// Limit values of implementation-specific int type.
-const (
-	MaxInt = int(^uint(0) >> 1)
-	MinInt = -MaxInt - 1
-)
-
-// -- block ------------------------------------------------------------
-
-// A set is represented as a circular doubly-linked list of blocks,
-// each containing an offset and a bit array of fixed size
-// bitsPerBlock; the blocks are ordered by increasing offset.
-//
-// The set contains an element x iff the block whose offset is x - (x
-// mod bitsPerBlock) has the bit (x mod bitsPerBlock) set, where mod
-// is the Euclidean remainder.
-//
-// A block may only be empty transiently.
-//
-type block struct {
-	offset     int                 // offset mod bitsPerBlock == 0
-	bits       [wordsPerBlock]word // contains at least one set bit
-	next, prev *block              // doubly-linked list of blocks
-}
-
-// wordMask returns the word index (in block.bits)
-// and single-bit mask for the block's ith bit.
-func wordMask(i uint) (w uint, mask word) {
-	w = i / bitsPerWord
-	mask = 1 << (i % bitsPerWord)
-	return
-}
-
-// insert sets the block b's ith bit and
-// returns true if it was not already set.
-//
-func (b *block) insert(i uint) bool {
-	w, mask := wordMask(i)
-	if b.bits[w]&mask == 0 {
-		b.bits[w] |= mask
-		return true
-	}
-	return false
-}
-
-// remove clears the block's ith bit and
-// returns true if the bit was previously set.
-// NB: may leave the block empty.
-//
-func (b *block) remove(i uint) bool {
-	w, mask := wordMask(i)
-	if b.bits[w]&mask != 0 {
-		b.bits[w] &^= mask
-		return true
-	}
-	return false
-}
-
-// has reports whether the block's ith bit is set.
-func (b *block) has(i uint) bool {
-	w, mask := wordMask(i)
-	return b.bits[w]&mask != 0
-}
-
-// empty reports whether b.len()==0, but more efficiently.
-func (b *block) empty() bool {
-	for _, w := range b.bits {
-		if w != 0 {
-			return false
-		}
-	}
-	return true
-}
-
-// len returns the number of set bits in block b.
-func (b *block) len() int {
-	var l int
-	for _, w := range b.bits {
-		l += popcount(w)
-	}
-	return l
-}
-
-// max returns the maximum element of the block.
-// The block must not be empty.
-func (b *block) max() int {
-	bi := b.offset + bitsPerBlock
-	// Decrement bi by number of high zeros in last.bits.
-	for i := len(b.bits) - 1; i >= 0; i-- {
-		if w := b.bits[i]; w != 0 {
-			return bi - nlz(w) - 1
-		}
-		bi -= bitsPerWord
-	}
-	panic("BUG: empty block")
-}
-
-// min returns the minimum element of the block,
-// and also removes it if take is set.
-// The block must not be initially empty.
-// NB: may leave the block empty.
-func (b *block) min(take bool) int {
-	for i, w := range b.bits {
-		if w != 0 {
-			tz := ntz(w)
-			if take {
-				b.bits[i] = w &^ (1 << uint(tz))
-			}
-			return b.offset + int(i*bitsPerWord) + tz
-		}
-	}
-	panic("BUG: empty block")
-}
-
-// lowerBound returns the smallest element of the block that is greater than or
-// equal to the element corresponding to the ith bit. If there is no such
-// element, the second return value is false.
-func (b *block) lowerBound(i uint) (int, bool) {
-	w := i / bitsPerWord
-	bit := i % bitsPerWord
-
-	if val := b.bits[w] >> bit; val != 0 {
-		return b.offset + int(i) + ntz(val), true
-	}
-
-	for w++; w < wordsPerBlock; w++ {
-		if val := b.bits[w]; val != 0 {
-			return b.offset + int(w*bitsPerWord) + ntz(val), true
-		}
-	}
-
-	return 0, false
-}
-
-// forEach calls f for each element of block b.
-// f must not mutate b's enclosing Sparse.
-func (b *block) forEach(f func(int)) {
-	for i, w := range b.bits {
-		offset := b.offset + i*bitsPerWord
-		for bi := 0; w != 0 && bi < bitsPerWord; bi++ {
-			if w&1 != 0 {
-				f(offset)
-			}
-			offset++
-			w >>= 1
-		}
-	}
-}
-
-// offsetAndBitIndex returns the offset of the block that would
-// contain x and the bit index of x within that block.
-//
-func offsetAndBitIndex(x int) (int, uint) {
-	mod := x % bitsPerBlock
-	if mod < 0 {
-		// Euclidean (non-negative) remainder
-		mod += bitsPerBlock
-	}
-	return x - mod, uint(mod)
-}
-
-// -- Sparse --------------------------------------------------------------
-
-// none is a shared, empty, sentinel block that indicates the end of a block
-// list.
-var none block
-
-// Dummy type used to generate an implicit panic. This must be defined at the
-// package level; if it is defined inside a function, it prevents the inlining
-// of that function.
-type to_copy_a_sparse_you_must_call_its_Copy_method struct{}
-
-// init ensures s is properly initialized.
-func (s *Sparse) init() {
-	root := &s.root
-	if root.next == nil {
-		root.offset = MaxInt
-		root.next = root
-		root.prev = root
-	} else if root.next.prev != root {
-		// Copying a Sparse x leads to pernicious corruption: the
-		// new Sparse y shares the old linked list, but iteration
-		// on y will never encounter &y.root so it goes into a
-		// loop.  Fail fast before this occurs.
-		// We don't want to call panic here because it prevents the
-		// inlining of this function.
-		_ = (interface{}(nil)).(to_copy_a_sparse_you_must_call_its_Copy_method)
-	}
-}
-
-func (s *Sparse) first() *block {
-	s.init()
-	if s.root.offset == MaxInt {
-		return &none
-	}
-	return &s.root
-}
-
-// next returns the next block in the list, or end if b is the last block.
-func (s *Sparse) next(b *block) *block {
-	if b.next == &s.root {
-		return &none
-	}
-	return b.next
-}
-
-// prev returns the previous block in the list, or end if b is the first block.
-func (s *Sparse) prev(b *block) *block {
-	if b.prev == &s.root {
-		return &none
-	}
-	return b.prev
-}
-
-// IsEmpty reports whether the set s is empty.
-func (s *Sparse) IsEmpty() bool {
-	return s.root.next == nil || s.root.offset == MaxInt
-}
-
-// Len returns the number of elements in the set s.
-func (s *Sparse) Len() int {
-	var l int
-	for b := s.first(); b != &none; b = s.next(b) {
-		l += b.len()
-	}
-	return l
-}
-
-// Max returns the maximum element of the set s, or MinInt if s is empty.
-func (s *Sparse) Max() int {
-	if s.IsEmpty() {
-		return MinInt
-	}
-	return s.root.prev.max()
-}
-
-// Min returns the minimum element of the set s, or MaxInt if s is empty.
-func (s *Sparse) Min() int {
-	if s.IsEmpty() {
-		return MaxInt
-	}
-	return s.root.min(false)
-}
-
-// LowerBound returns the smallest element >= x, or MaxInt if there is no such
-// element.
-func (s *Sparse) LowerBound(x int) int {
-	offset, i := offsetAndBitIndex(x)
-	for b := s.first(); b != &none; b = s.next(b) {
-		if b.offset > offset {
-			return b.min(false)
-		}
-		if b.offset == offset {
-			if y, ok := b.lowerBound(i); ok {
-				return y
-			}
-		}
-	}
-	return MaxInt
-}
-
-// block returns the block that would contain offset,
-// or nil if s contains no such block.
-// Precondition: offset is a multiple of bitsPerBlock.
-func (s *Sparse) block(offset int) *block {
-	for b := s.first(); b != &none && b.offset <= offset; b = s.next(b) {
-		if b.offset == offset {
-			return b
-		}
-	}
-	return nil
-}
-
-// Insert adds x to the set s, and reports whether the set grew.
-func (s *Sparse) Insert(x int) bool {
-	offset, i := offsetAndBitIndex(x)
-
-	b := s.first()
-	for ; b != &none && b.offset <= offset; b = s.next(b) {
-		if b.offset == offset {
-			return b.insert(i)
-		}
-	}
-
-	// Insert new block before b.
-	new := s.insertBlockBefore(b)
-	new.offset = offset
-	return new.insert(i)
-}
-
-// removeBlock removes a block and returns the block that followed it (or end if
-// it was the last block).
-func (s *Sparse) removeBlock(b *block) *block {
-	if b != &s.root {
-		b.prev.next = b.next
-		b.next.prev = b.prev
-		if b.next == &s.root {
-			return &none
-		}
-		return b.next
-	}
-
-	first := s.root.next
-	if first == &s.root {
-		// This was the only block.
-		s.Clear()
-		return &none
-	}
-	s.root.offset = first.offset
-	s.root.bits = first.bits
-	if first.next == &s.root {
-		// Single block remaining.
-		s.root.next = &s.root
-		s.root.prev = &s.root
-	} else {
-		s.root.next = first.next
-		first.next.prev = &s.root
-	}
-	return &s.root
-}
-
-// Remove removes x from the set s, and reports whether the set shrank.
-func (s *Sparse) Remove(x int) bool {
-	offset, i := offsetAndBitIndex(x)
-	if b := s.block(offset); b != nil {
-		if !b.remove(i) {
-			return false
-		}
-		if b.empty() {
-			s.removeBlock(b)
-		}
-		return true
-	}
-	return false
-}
-
-// Clear removes all elements from the set s.
-func (s *Sparse) Clear() {
-	s.root = block{
-		offset: MaxInt,
-		next:   &s.root,
-		prev:   &s.root,
-	}
-}
-
-// If set s is non-empty, TakeMin sets *p to the minimum element of
-// the set s, removes that element from the set and returns true.
-// Otherwise, it returns false and *p is undefined.
-//
-// This method may be used for iteration over a worklist like so:
-//
-// 	var x int
-// 	for worklist.TakeMin(&x) { use(x) }
-//
-func (s *Sparse) TakeMin(p *int) bool {
-	if s.IsEmpty() {
-		return false
-	}
-	*p = s.root.min(true)
-	if s.root.empty() {
-		s.removeBlock(&s.root)
-	}
-	return true
-}
-
-// Has reports whether x is an element of the set s.
-func (s *Sparse) Has(x int) bool {
-	offset, i := offsetAndBitIndex(x)
-	if b := s.block(offset); b != nil {
-		return b.has(i)
-	}
-	return false
-}
-
-// forEach applies function f to each element of the set s in order.
-//
-// f must not mutate s.  Consequently, forEach is not safe to expose
-// to clients.  In any case, using "range s.AppendTo()" allows more
-// natural control flow with continue/break/return.
-//
-func (s *Sparse) forEach(f func(int)) {
-	for b := s.first(); b != &none; b = s.next(b) {
-		b.forEach(f)
-	}
-}
-
-// Copy sets s to the value of x.
-func (s *Sparse) Copy(x *Sparse) {
-	if s == x {
-		return
-	}
-
-	xb := x.first()
-	sb := s.first()
-	for xb != &none {
-		if sb == &none {
-			sb = s.insertBlockBefore(sb)
-		}
-		sb.offset = xb.offset
-		sb.bits = xb.bits
-		xb = x.next(xb)
-		sb = s.next(sb)
-	}
-	s.discardTail(sb)
-}
-
-// insertBlockBefore returns a new block, inserting it before next.
-// If next is the root, the root is replaced. If next is end, the block is
-// inserted at the end.
-func (s *Sparse) insertBlockBefore(next *block) *block {
-	if s.IsEmpty() {
-		if next != &none {
-			panic("BUG: passed block with empty set")
-		}
-		return &s.root
-	}
-
-	if next == &s.root {
-		// Special case: we need to create a new block that will become the root
-		// block.The old root block becomes the second block.
-		second := s.root
-		s.root = block{
-			next: &second,
-		}
-		if second.next == &s.root {
-			s.root.prev = &second
-		} else {
-			s.root.prev = second.prev
-			second.next.prev = &second
-			second.prev = &s.root
-		}
-		return &s.root
-	}
-	if next == &none {
-		// Insert before root.
-		next = &s.root
-	}
-	b := new(block)
-	b.next = next
-	b.prev = next.prev
-	b.prev.next = b
-	next.prev = b
-	return b
-}
-
-// discardTail removes block b and all its successors from s.
-func (s *Sparse) discardTail(b *block) {
-	if b != &none {
-		if b == &s.root {
-			s.Clear()
-		} else {
-			b.prev.next = &s.root
-			s.root.prev = b.prev
-		}
-	}
-}
-
-// IntersectionWith sets s to the intersection s ∩ x.
-func (s *Sparse) IntersectionWith(x *Sparse) {
-	if s == x {
-		return
-	}
-
-	xb := x.first()
-	sb := s.first()
-	for xb != &none && sb != &none {
-		switch {
-		case xb.offset < sb.offset:
-			xb = x.next(xb)
-
-		case xb.offset > sb.offset:
-			sb = s.removeBlock(sb)
-
-		default:
-			var sum word
-			for i := range sb.bits {
-				r := xb.bits[i] & sb.bits[i]
-				sb.bits[i] = r
-				sum |= r
-			}
-			if sum != 0 {
-				sb = s.next(sb)
-			} else {
-				// sb will be overwritten or removed
-			}
-
-			xb = x.next(xb)
-		}
-	}
-
-	s.discardTail(sb)
-}
-
-// Intersection sets s to the intersection x ∩ y.
-func (s *Sparse) Intersection(x, y *Sparse) {
-	switch {
-	case s == x:
-		s.IntersectionWith(y)
-		return
-	case s == y:
-		s.IntersectionWith(x)
-		return
-	case x == y:
-		s.Copy(x)
-		return
-	}
-
-	xb := x.first()
-	yb := y.first()
-	sb := s.first()
-	for xb != &none && yb != &none {
-		switch {
-		case xb.offset < yb.offset:
-			xb = x.next(xb)
-			continue
-		case xb.offset > yb.offset:
-			yb = y.next(yb)
-			continue
-		}
-
-		if sb == &none {
-			sb = s.insertBlockBefore(sb)
-		}
-		sb.offset = xb.offset
-
-		var sum word
-		for i := range sb.bits {
-			r := xb.bits[i] & yb.bits[i]
-			sb.bits[i] = r
-			sum |= r
-		}
-		if sum != 0 {
-			sb = s.next(sb)
-		} else {
-			// sb will be overwritten or removed
-		}
-
-		xb = x.next(xb)
-		yb = y.next(yb)
-	}
-
-	s.discardTail(sb)
-}
-
-// Intersects reports whether s ∩ x ≠ ∅.
-func (s *Sparse) Intersects(x *Sparse) bool {
-	sb := s.first()
-	xb := x.first()
-	for sb != &none && xb != &none {
-		switch {
-		case xb.offset < sb.offset:
-			xb = x.next(xb)
-		case xb.offset > sb.offset:
-			sb = s.next(sb)
-		default:
-			for i := range sb.bits {
-				if sb.bits[i]&xb.bits[i] != 0 {
-					return true
-				}
-			}
-			sb = s.next(sb)
-			xb = x.next(xb)
-		}
-	}
-	return false
-}
-
-// UnionWith sets s to the union s ∪ x, and reports whether s grew.
-func (s *Sparse) UnionWith(x *Sparse) bool {
-	if s == x {
-		return false
-	}
-
-	var changed bool
-	xb := x.first()
-	sb := s.first()
-	for xb != &none {
-		if sb != &none && sb.offset == xb.offset {
-			for i := range xb.bits {
-				if sb.bits[i] != xb.bits[i] {
-					sb.bits[i] |= xb.bits[i]
-					changed = true
-				}
-			}
-			xb = x.next(xb)
-		} else if sb == &none || sb.offset > xb.offset {
-			sb = s.insertBlockBefore(sb)
-			sb.offset = xb.offset
-			sb.bits = xb.bits
-			changed = true
-
-			xb = x.next(xb)
-		}
-		sb = s.next(sb)
-	}
-	return changed
-}
-
-// Union sets s to the union x ∪ y.
-func (s *Sparse) Union(x, y *Sparse) {
-	switch {
-	case x == y:
-		s.Copy(x)
-		return
-	case s == x:
-		s.UnionWith(y)
-		return
-	case s == y:
-		s.UnionWith(x)
-		return
-	}
-
-	xb := x.first()
-	yb := y.first()
-	sb := s.first()
-	for xb != &none || yb != &none {
-		if sb == &none {
-			sb = s.insertBlockBefore(sb)
-		}
-		switch {
-		case yb == &none || (xb != &none && xb.offset < yb.offset):
-			sb.offset = xb.offset
-			sb.bits = xb.bits
-			xb = x.next(xb)
-
-		case xb == &none || (yb != &none && yb.offset < xb.offset):
-			sb.offset = yb.offset
-			sb.bits = yb.bits
-			yb = y.next(yb)
-
-		default:
-			sb.offset = xb.offset
-			for i := range xb.bits {
-				sb.bits[i] = xb.bits[i] | yb.bits[i]
-			}
-			xb = x.next(xb)
-			yb = y.next(yb)
-		}
-		sb = s.next(sb)
-	}
-
-	s.discardTail(sb)
-}
-
-// DifferenceWith sets s to the difference s ∖ x.
-func (s *Sparse) DifferenceWith(x *Sparse) {
-	if s == x {
-		s.Clear()
-		return
-	}
-
-	xb := x.first()
-	sb := s.first()
-	for xb != &none && sb != &none {
-		switch {
-		case xb.offset > sb.offset:
-			sb = s.next(sb)
-
-		case xb.offset < sb.offset:
-			xb = x.next(xb)
-
-		default:
-			var sum word
-			for i := range sb.bits {
-				r := sb.bits[i] & ^xb.bits[i]
-				sb.bits[i] = r
-				sum |= r
-			}
-			if sum == 0 {
-				sb = s.removeBlock(sb)
-			} else {
-				sb = s.next(sb)
-			}
-			xb = x.next(xb)
-		}
-	}
-}
-
-// Difference sets s to the difference x ∖ y.
-func (s *Sparse) Difference(x, y *Sparse) {
-	switch {
-	case x == y:
-		s.Clear()
-		return
-	case s == x:
-		s.DifferenceWith(y)
-		return
-	case s == y:
-		var y2 Sparse
-		y2.Copy(y)
-		s.Difference(x, &y2)
-		return
-	}
-
-	xb := x.first()
-	yb := y.first()
-	sb := s.first()
-	for xb != &none && yb != &none {
-		if xb.offset > yb.offset {
-			// y has block, x has &none
-			yb = y.next(yb)
-			continue
-		}
-
-		if sb == &none {
-			sb = s.insertBlockBefore(sb)
-		}
-		sb.offset = xb.offset
-
-		switch {
-		case xb.offset < yb.offset:
-			// x has block, y has &none
-			sb.bits = xb.bits
-
-			sb = s.next(sb)
-
-		default:
-			// x and y have corresponding blocks
-			var sum word
-			for i := range sb.bits {
-				r := xb.bits[i] & ^yb.bits[i]
-				sb.bits[i] = r
-				sum |= r
-			}
-			if sum != 0 {
-				sb = s.next(sb)
-			} else {
-				// sb will be overwritten or removed
-			}
-
-			yb = y.next(yb)
-		}
-		xb = x.next(xb)
-	}
-
-	for xb != &none {
-		if sb == &none {
-			sb = s.insertBlockBefore(sb)
-		}
-		sb.offset = xb.offset
-		sb.bits = xb.bits
-		sb = s.next(sb)
-
-		xb = x.next(xb)
-	}
-
-	s.discardTail(sb)
-}
-
-// SymmetricDifferenceWith sets s to the symmetric difference s ∆ x.
-func (s *Sparse) SymmetricDifferenceWith(x *Sparse) {
-	if s == x {
-		s.Clear()
-		return
-	}
-
-	sb := s.first()
-	xb := x.first()
-	for xb != &none && sb != &none {
-		switch {
-		case sb.offset < xb.offset:
-			sb = s.next(sb)
-		case xb.offset < sb.offset:
-			nb := s.insertBlockBefore(sb)
-			nb.offset = xb.offset
-			nb.bits = xb.bits
-			xb = x.next(xb)
-		default:
-			var sum word
-			for i := range sb.bits {
-				r := sb.bits[i] ^ xb.bits[i]
-				sb.bits[i] = r
-				sum |= r
-			}
-			if sum == 0 {
-				sb = s.removeBlock(sb)
-			} else {
-				sb = s.next(sb)
-			}
-			xb = x.next(xb)
-		}
-	}
-
-	for xb != &none { // append the tail of x to s
-		sb = s.insertBlockBefore(sb)
-		sb.offset = xb.offset
-		sb.bits = xb.bits
-		sb = s.next(sb)
-		xb = x.next(xb)
-	}
-}
-
-// SymmetricDifference sets s to the symmetric difference x ∆ y.
-func (s *Sparse) SymmetricDifference(x, y *Sparse) {
-	switch {
-	case x == y:
-		s.Clear()
-		return
-	case s == x:
-		s.SymmetricDifferenceWith(y)
-		return
-	case s == y:
-		s.SymmetricDifferenceWith(x)
-		return
-	}
-
-	sb := s.first()
-	xb := x.first()
-	yb := y.first()
-	for xb != &none && yb != &none {
-		if sb == &none {
-			sb = s.insertBlockBefore(sb)
-		}
-		switch {
-		case yb.offset < xb.offset:
-			sb.offset = yb.offset
-			sb.bits = yb.bits
-			sb = s.next(sb)
-			yb = y.next(yb)
-		case xb.offset < yb.offset:
-			sb.offset = xb.offset
-			sb.bits = xb.bits
-			sb = s.next(sb)
-			xb = x.next(xb)
-		default:
-			var sum word
-			for i := range sb.bits {
-				r := xb.bits[i] ^ yb.bits[i]
-				sb.bits[i] = r
-				sum |= r
-			}
-			if sum != 0 {
-				sb.offset = xb.offset
-				sb = s.next(sb)
-			}
-			xb = x.next(xb)
-			yb = y.next(yb)
-		}
-	}
-
-	for xb != &none { // append the tail of x to s
-		if sb == &none {
-			sb = s.insertBlockBefore(sb)
-		}
-		sb.offset = xb.offset
-		sb.bits = xb.bits
-		sb = s.next(sb)
-		xb = x.next(xb)
-	}
-
-	for yb != &none { // append the tail of y to s
-		if sb == &none {
-			sb = s.insertBlockBefore(sb)
-		}
-		sb.offset = yb.offset
-		sb.bits = yb.bits
-		sb = s.next(sb)
-		yb = y.next(yb)
-	}
-
-	s.discardTail(sb)
-}
-
-// SubsetOf reports whether s ∖ x = ∅.
-func (s *Sparse) SubsetOf(x *Sparse) bool {
-	if s == x {
-		return true
-	}
-
-	sb := s.first()
-	xb := x.first()
-	for sb != &none {
-		switch {
-		case xb == &none || xb.offset > sb.offset:
-			return false
-		case xb.offset < sb.offset:
-			xb = x.next(xb)
-		default:
-			for i := range sb.bits {
-				if sb.bits[i]&^xb.bits[i] != 0 {
-					return false
-				}
-			}
-			sb = s.next(sb)
-			xb = x.next(xb)
-		}
-	}
-	return true
-}
-
-// Equals reports whether the sets s and t have the same elements.
-func (s *Sparse) Equals(t *Sparse) bool {
-	if s == t {
-		return true
-	}
-	sb := s.first()
-	tb := t.first()
-	for {
-		switch {
-		case sb == &none && tb == &none:
-			return true
-		case sb == &none || tb == &none:
-			return false
-		case sb.offset != tb.offset:
-			return false
-		case sb.bits != tb.bits:
-			return false
-		}
-
-		sb = s.next(sb)
-		tb = t.next(tb)
-	}
-}
-
-// String returns a human-readable description of the set s.
-func (s *Sparse) String() string {
-	var buf bytes.Buffer
-	buf.WriteByte('{')
-	s.forEach(func(x int) {
-		if buf.Len() > 1 {
-			buf.WriteByte(' ')
-		}
-		fmt.Fprintf(&buf, "%d", x)
-	})
-	buf.WriteByte('}')
-	return buf.String()
-}
-
-// BitString returns the set as a string of 1s and 0s denoting the sum
-// of the i'th powers of 2, for each i in s.  A radix point, always
-// preceded by a digit, appears if the sum is non-integral.
-//
-// Examples:
-//              {}.BitString() =      "0"
-//           {4,5}.BitString() = "110000"
-//            {-3}.BitString() =      "0.001"
-//      {-3,0,4,5}.BitString() = "110001.001"
-//
-func (s *Sparse) BitString() string {
-	if s.IsEmpty() {
-		return "0"
-	}
-
-	min, max := s.Min(), s.Max()
-	var nbytes int
-	if max > 0 {
-		nbytes = max
-	}
-	nbytes++ // zero bit
-	radix := nbytes
-	if min < 0 {
-		nbytes += len(".") - min
-	}
-
-	b := make([]byte, nbytes)
-	for i := range b {
-		b[i] = '0'
-	}
-	if radix < nbytes {
-		b[radix] = '.'
-	}
-	s.forEach(func(x int) {
-		if x >= 0 {
-			x += len(".")
-		}
-		b[radix-x] = '1'
-	})
-	return string(b)
-}
-
-// GoString returns a string showing the internal representation of
-// the set s.
-//
-func (s *Sparse) GoString() string {
-	var buf bytes.Buffer
-	for b := s.first(); b != &none; b = s.next(b) {
-		fmt.Fprintf(&buf, "block %p {offset=%d next=%p prev=%p",
-			b, b.offset, b.next, b.prev)
-		for _, w := range b.bits {
-			fmt.Fprintf(&buf, " 0%016x", w)
-		}
-		fmt.Fprintf(&buf, "}\n")
-	}
-	return buf.String()
-}
-
-// AppendTo returns the result of appending the elements of s to slice
-// in order.
-func (s *Sparse) AppendTo(slice []int) []int {
-	s.forEach(func(x int) {
-		slice = append(slice, x)
-	})
-	return slice
-}
-
-// -- Testing/debugging ------------------------------------------------
-
-// check returns an error if the representation invariants of s are violated.
-func (s *Sparse) check() error {
-	s.init()
-	if s.root.empty() {
-		// An empty set must have only the root block with offset MaxInt.
-		if s.root.next != &s.root {
-			return fmt.Errorf("multiple blocks with empty root block")
-		}
-		if s.root.offset != MaxInt {
-			return fmt.Errorf("empty set has offset %d, should be MaxInt", s.root.offset)
-		}
-		return nil
-	}
-	for b := s.first(); ; b = s.next(b) {
-		if b.offset%bitsPerBlock != 0 {
-			return fmt.Errorf("bad offset modulo: %d", b.offset)
-		}
-		if b.empty() {
-			return fmt.Errorf("empty block")
-		}
-		if b.prev.next != b {
-			return fmt.Errorf("bad prev.next link")
-		}
-		if b.next.prev != b {
-			return fmt.Errorf("bad next.prev link")
-		}
-		if b.next == &s.root {
-			break
-		}
-		if b.offset >= b.next.offset {
-			return fmt.Errorf("bad offset order: b.offset=%d, b.next.offset=%d",
-				b.offset, b.next.offset)
-		}
-	}
-	return nil
-}
diff --git a/vendor/golang.org/x/tools/container/intsets/util.go b/vendor/golang.org/x/tools/container/intsets/util.go
deleted file mode 100644
index dd1db86..0000000
--- a/vendor/golang.org/x/tools/container/intsets/util.go
+++ /dev/null
@@ -1,84 +0,0 @@
-// Copyright 2013 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package intsets
-
-// From Hacker's Delight, fig 5.2.
-func popcountHD(x uint32) int {
-	x -= (x >> 1) & 0x55555555
-	x = (x & 0x33333333) + ((x >> 2) & 0x33333333)
-	x = (x + (x >> 4)) & 0x0f0f0f0f
-	x = x + (x >> 8)
-	x = x + (x >> 16)
-	return int(x & 0x0000003f)
-}
-
-var a [1 << 8]byte
-
-func init() {
-	for i := range a {
-		var n byte
-		for x := i; x != 0; x >>= 1 {
-			if x&1 != 0 {
-				n++
-			}
-		}
-		a[i] = n
-	}
-}
-
-func popcountTable(x word) int {
-	return int(a[byte(x>>(0*8))] +
-		a[byte(x>>(1*8))] +
-		a[byte(x>>(2*8))] +
-		a[byte(x>>(3*8))] +
-		a[byte(x>>(4*8))] +
-		a[byte(x>>(5*8))] +
-		a[byte(x>>(6*8))] +
-		a[byte(x>>(7*8))])
-}
-
-// nlz returns the number of leading zeros of x.
-// From Hacker's Delight, fig 5.11.
-func nlz(x word) int {
-	x |= (x >> 1)
-	x |= (x >> 2)
-	x |= (x >> 4)
-	x |= (x >> 8)
-	x |= (x >> 16)
-	x |= (x >> 32)
-	return popcount(^x)
-}
-
-// ntz returns the number of trailing zeros of x.
-// From Hacker's Delight, fig 5.13.
-func ntz(x word) int {
-	if x == 0 {
-		return bitsPerWord
-	}
-	n := 1
-	if bitsPerWord == 64 {
-		if (x & 0xffffffff) == 0 {
-			n = n + 32
-			x = x >> 32
-		}
-	}
-	if (x & 0x0000ffff) == 0 {
-		n = n + 16
-		x = x >> 16
-	}
-	if (x & 0x000000ff) == 0 {
-		n = n + 8
-		x = x >> 8
-	}
-	if (x & 0x0000000f) == 0 {
-		n = n + 4
-		x = x >> 4
-	}
-	if (x & 0x00000003) == 0 {
-		n = n + 2
-		x = x >> 2
-	}
-	return n - int(x&1)
-}
diff --git a/vendor/golang.org/x/tools/go.mod b/vendor/golang.org/x/tools/go.mod
deleted file mode 100644
index 0984a83..0000000
--- a/vendor/golang.org/x/tools/go.mod
+++ /dev/null
@@ -1,8 +0,0 @@
-module golang.org/x/tools
-
-go 1.11
-
-require (
-	golang.org/x/net v0.0.0-20190311183353-d8887717615a
-	golang.org/x/sync v0.0.0-20190423024810-112230192c58
-)