Update third_party/protobuf to protobuf-v3.0.0-beta-3

third_party/protobuf/ruby/README.md

 This directory contains the Ruby extension that implements Protocol Buffers
 functionality in Ruby.
 
 The Ruby extension makes use of generated Ruby code that defines message and
 enum types in a Ruby DSL. You may write definitions in this DSL directly, but
 we recommend using protoc's Ruby generation support with .proto files. The
 build process in this directory only installs the extension; you need to
 install protoc as well to have Ruby code generation functionality.
 
 Installation from Gem
@@ skipping 14 matching lines @@
 However, if you wish to generate the Ruby DSL from a `.proto` file, you will
 also want to install Protocol Buffers itself, as described in this repository's
 main `README` file. The version of `protoc` included in the latest release
 supports the `--ruby_out` option to generate Ruby code.
 
 A simple example of using the Ruby extension follows. More extensive
 documentation may be found in the RubyDoc comments (`call-seq` tags) in the
 source, and we plan to release separate, more detailed, documentation at a
 later date.
 
-    require 'google/protobuf'
+```ruby
+require 'google/protobuf'
 
-    # generated from my_proto_types.proto with protoc:
-    #  $ protoc --ruby_out=. my_proto_types.proto
-    require 'my_proto_types'
+# generated from my_proto_types.proto with protoc:
+#  $ protoc --ruby_out=. my_proto_types.proto
+require 'my_proto_types'
 
-    mymessage = MyTestMessage.new(:field1 => 42, :field2 => ["a", "b", "c"])
-    mymessage.field1 = 43
-    mymessage.field2.push("d")
-    mymessage.field3 = SubMessage.new(:foo => 100)
+mymessage = MyTestMessage.new(:field1 => 42, :field2 => ["a", "b", "c"])
+mymessage.field1 = 43
+mymessage.field2.push("d")
+mymessage.field3 = SubMessage.new(:foo => 100)
 
-    encoded_data = MyTestMessage.encode(mymessage)
-    decoded = MyTestMessage.decode(encoded_data)
-    assert decoded == mymessage
+encoded_data = MyTestMessage.encode(mymessage)
+decoded = MyTestMessage.decode(encoded_data)
+assert decoded == mymessage
 
-    puts "JSON:"
-    puts MyTestMessage.encode_json(mymessage)
+puts "JSON:"
+puts MyTestMessage.encode_json(mymessage)
+```
 
 Installation from Source (Building Gem)
 ---------------------------------------
 
 To build this Ruby extension, you will need:
 
 * Rake
 * Bundler
 * Ruby development headers
 * a C compiler
@@ skipping 41 matching lines @@
   to upload a new version of the gem to fix an issue, the version becomes
   "3.0.0.alpha.2.1" or "3.0.0.1".
 * If we are working on a prerelease version, we append a prerelease tag:
   "3.0.0.alpha.3.0.pre". The prerelease tag comes at the end so that when
   version numbers are sorted, any prerelease builds are ordered between the
   prior version and current version.
 
 These rules are designed to work with the sorting rules for
 [Gem::Version](http://ruby-doc.org/stdlib-2.0/libdoc/rubygems/rdoc/Gem/Version.html):
 release numbers should sort in actual release order.