add value_to_name to enum field
add value_to_name to enum field

localshred/protobuf,ruby-protobuf/protobuf,film42/protobuf,brianstien/protobuf,ruby-protobuf/protobuf,brianstien/protobuf,lookout/protobuffy,quixoten/protobuf,film42/protobuf,lookout/protobuffy,localshred/protobuf,zanker/protobuf,quixoten/protobuf,zanker/protobuf