Merge github.com:grpc/grpc into configurable-lookahead

Makefile

binding.gyp

build.yaml

doc/grpc-auth-support.md

doc/interop-test-descriptions.md

examples/cpp/cpptutorial.md

examples/cpp/helloworld/README.md

examples/cpp/helloworld/greeter_async_client.cc

examples/cpp/helloworld/greeter_client.cc

examples/cpp/route_guide/route_guide_client.cc

examples/python/helloworld/greeter_server.py

include/grpc++/channel.h

include/grpc++/client_context.h

include/grpc++/create_channel.h

include/grpc++/impl/thd_no_cxx11.h

include/grpc++/security/credentials.h

include/grpc++/support/channel_arguments.h

include/grpc++/support/time.h

include/grpc/grpc.h

include/grpc/grpc_security.h