generates a golang http-api from a proto3 file

does not support streams

testHttp.pb.go provides a goji.Web Mux, which can be used with an go webserver

it is designed to make a service available through json/http1 and grpc. 
Therefore it depends on the grpc file created protoc-gen-go and adds a second file for the json/http1-api

example:
```
mkdir -p goservice
ln -s test.proto testHttp.proto
protoc testHttp.proto --plugin=     --goweb_out=plugins=grpc:goservice
protoc test.proto     --plugin=        --go_out=plugins=grpc:goservice
```