CHANGES:
- Fix name resolution leading to wrongly mapped named
- Fix codegen bug causing the plugin to reject valid protobuf
- Add preliminary support for melange though disabling eager
evaluation of serialize and deserialize functions when not using
native or bytecode backends - Fix missing cflags when compiling test c stub
- Make Map tests compatible with older versions of protoc
- Fix negative integer test failues due to a bug in older versions of protobuf (google) c lib