Merge pull request #61 from zimmski/undocumented-fields

Some field tags are undocumented
diff --git a/flags.go b/flags.go
index 3a1c7aa..fb0d1fd 100644
--- a/flags.go
+++ b/flags.go
@@ -60,35 +60,44 @@
 // and Unmarshaler interfaces.
 //
 // Available field tags:
-//     short:          the short name of the option (single character)
-//     long:           the long name of the option
-//     description:    the description of the option (optional)
+//     short:            the short name of the option (single character)
+//     long:             the long name of the option
+//     required:         whether an option is required to appear on the command
+//                       line. If a required option is not present, the parser will
+//                       return ErrRequired (optional)
+//     description:      the description of the option (optional)
+//     long-description: the long description of the option. Currently only
+//                       displayed in generated man pages (optional)
+//     no-flag:          if non-empty this field is ignored as an option (optional)
+//
 //     optional:       whether an argument of the option is optional (optional)
 //     optional-value: the value of an optional option when the option occurs
 //                     without an argument. This tag can be specified multiple
 //                     times in the case of maps or slices (optional)
 //     default:        the default value of an option. This tag can be specified
-//                     multiple times in the case of slices or maps (optional).
+//                     multiple times in the case of slices or maps (optional)
 //     default-mask:   when specified, this value will be displayed in the help
 //                     instead of the actual default value. This is useful
 //                     mostly for hiding otherwise sensitive information from
 //                     showing up in the help. If default-mask takes the special
 //                     value "-", then no default value will be shown at all
 //                     (optional)
-//     required:       whether an option is required to appear on the command
-//                     line. If a required option is not present, the parser
-//                     will return ErrRequired.
-//     base:           a base (radix) used to convert strings to integer values,
-//                     the default base is 10 (i.e. decimal) (optional)
 //     value-name:     the name of the argument value (to be shown in the help,
 //                     (optional)
-//     group:          when specified on a struct field, makes the struct field
-//                     a separate group with the given name (optional).
-//     command:        when specified on a struct field, makes the struct field
-//                     a (sub)command with the given name (optional).
 //
+//     base: a base (radix) used to convert strings to integer values, the
+//           default base is 10 (i.e. decimal) (optional)
+//
+//     ini-name:       the explicit ini option name (optional)
+//     no-ini:         if non-empty this field is ignored as an ini option
+//                     (optional)
+//
+//     group:                when specified on a struct field, makes the struct
+//                           field a separate group with the given name (optional)
+//     command:              when specified on a struct field, makes the struct
+//                           field a (sub)command with the given name (optional)
 //     subcommands-optional: when specified on a command struct field, makes
-//                           any subcommands of that command optional.
+//                           any subcommands of that command optional
 //
 // Either short: or long: must be specified to make the field eligible as an
 // option.