move grpc-common examples to here

grpc-common/LICENSE

grpc-common/PATENTS

grpc-common/PROTOCOL-HTTP2.md

grpc-common/README.md

grpc-common/cpp/README.md

grpc-common/cpp/cpptutorial.md

grpc-common/cpp/helloworld/Makefile

grpc-common/cpp/helloworld/README.md

grpc-common/cpp/helloworld/greeter_async_client.cc

grpc-common/cpp/helloworld/greeter_async_server.cc

grpc-common/cpp/helloworld/greeter_client.cc

grpc-common/cpp/helloworld/greeter_server.cc

grpc-common/cpp/route_guide/Makefile

grpc-common/cpp/route_guide/helper.cc

grpc-common/cpp/route_guide/helper.h

grpc-common/cpp/route_guide/route_guide_client.cc

grpc-common/cpp/route_guide/route_guide_db.json

grpc-common/cpp/route_guide/route_guide_server.cc

grpc-common/csharp/.gitignore

grpc-common/csharp/.nuget/packages.config