Merge remote-tracking branch 'upstream/master' into import

BUILD

CONTRIBUTING.md

Makefile

binding.gyp

build.yaml

config.m4

doc/compression.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

examples/csharp/helloworld/Greeter/packages.config

...ples/csharp/helloworld/GreeterClient/GreeterClient.csproj

examples/csharp/helloworld/GreeterClient/Program.cs

examples/csharp/helloworld/GreeterClient/packages.config

...ples/csharp/helloworld/GreeterServer/GreeterServer.csproj

examples/csharp/helloworld/GreeterServer/packages.config

examples/csharp/helloworld/generate_protos.bat

examples/csharp/route_guide/.nuget/packages.config

examples/csharp/route_guide/RouteGuide/RouteGuide.cs