Merge remote-tracking branch 'google/master' into contrib-cmake

.travis.yml

BUILD

CONTRIBUTING.md

INSTALL.md

Makefile

PYTHON-MANIFEST.in

Rakefile

binding.gyp

build.yaml

config.m4

doc/PROTOCOL-HTTP2.md

doc/compression.md

doc/interop-test-descriptions.md

examples/cpp/README.md

examples/cpp/cpptutorial.md

examples/cpp/helloworld/README.md

examples/csharp/helloworld/.nuget/packages.config

examples/csharp/helloworld/Greeter/Greeter.csproj

examples/csharp/helloworld/Greeter/Helloworld.cs

examples/csharp/helloworld/Greeter/HelloworldGrpc.cs