Proto commits in bazelment/trunk

These 3 commits are when the Protocol Buffers files have changed:

Commit:7dbbc45
Author:Ming Zhao

Improve gRPC helloworld example from gRPC and gRPC-Java code. Add bazel BUILD.

The documentation is generated from this commit.

Commit:6d73ae2
Author:Ming Zhao

Deal with grpc issue https://github.com/grpc/grpc/issues/1256 by using an explicit package to set namespace.

Commit:8e63bbe
Author:Ming Zhao

Add example/bank.proto that uses grpc.