protoc-gen-echo

protoc-gen-echo is a protoc plugin which simply echos the incoming CodeGeneratorRequest to stderr.

```bash $ protoc --plugin=protoc-gen-echo -I proto --echo_out=. proto/example.proto

[echo start]

CodeGeneratorRequest will be available here to read in.

[echo end] ```

LICENSE

MIT or Apache 2.0. Pick whichever.