service-center support for grpc

1. Download ‘protoc’ compiler, https://github.com/google/protobuf/releases
2. git clone -b v1.0.0 https://github.com/golang/protobuf $GOPATH/src/github.com/golang/protobuf
3. Install the go-grpc plugin, go get github.com/golang/protobuf/protoc-gen-go
4. Compile the service.proto file, protoc --go_out=plugins=grpc:. services.proto