goprotobuf: Unexport a bunch of symbols in generator.go.
goprotobuf: Unexport a bunch of symbols in generator.go.

R=iant
CC=golang-dev
https://codereview.appspot.com/6894046

tamird/protobuf-2,trdata/protobuf,jmptrader/protobuf-1,golang/protobuf,hailocab/protobuf,ArtemTeleshev/go-protobuf,golang/protobuf,velocity-toolkit/protobuf-1,ekle/protoc-gen-goweb,tamird/protobuf-2,francoishill/protobuf,daemonl/protobuf,skyportsystems/go-protobuf,alskjstl/protobuf,fuchsia-mirror/third_party-github.com-golang-protobuf,ekle/protoc-gen-goweb_test,eduardiazf/protobuf,jeremyletang/protobuf,adnaan/protobuf,jrbarron/protobuf,fuchsia-mirror/third_party-github.com-golang-protobuf,qinlodestar/protobuf,trdata/protobuf,mwitkow-io/protobuf,csuideal/protobuf,skyportsystems/go-protobuf,kung-foo/protobuf,aoeu/protobuf,linkedin-inc/protobuf