Add protoc command to example/readme (#1653)

So users can copy the command and try with their own protos.
diff --git a/examples/README.md b/examples/README.md
index c35a263..792da24 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -30,29 +30,35 @@
 
 - Run the server
 
-```
-$ greeter_server &
-```
+  ```
+  $ greeter_server &
+  ```
 
 - Run the client
 
-```
-$ greeter_client
-```
+  ```
+  $ greeter_client
+  ```
 
 OPTIONAL - Rebuilding the generated code
 ----------------------------------------
 
-1 First [install protoc](https://github.com/google/protobuf/blob/master/README.md#protocol-compiler-installation)
+1. Install [protobuf compiler](https://github.com/google/protobuf/blob/master/README.md#protocol-compiler-installation)
 
-2 Install the protoc Go plugin.
+1. Install the protoc Go plugin
 
-```
-$ go get -a github.com/golang/protobuf/protoc-gen-go
-```
+   ```
+   $ go get -u github.com/golang/protobuf/protoc-gen-go
+   ```
 
-3 Rebuild the generated Go code.
+1. Rebuild the generated Go code
 
-```
-$ go generate google.golang.org/grpc/examples/helloworld/...
-```
+   ```
+   $ go generate google.golang.org/grpc/examples/helloworld/...
+   ```
+   
+   Or run `protoc` command (with the grpc plugin)
+   
+   ```
+   $ protoc -I helloworld/ helloworld/helloworld.proto --go_out=plugins=grpc:helloworld
+   ```