Merge pull request #1519 from jtattermusch/csharp_protoc_plugin

BUILD

Makefile

build.json

src/compiler/csharp_generator.cc

src/compiler/csharp_generator.h

src/compiler/csharp_generator_helpers.h

src/compiler/csharp_plugin.cc

src/compiler/generator_helpers.h

src/csharp/Grpc.Examples.MathClient/MathClient.cs

src/csharp/Grpc.Examples.MathServer/MathServer.cs

src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs

src/csharp/Grpc.Examples/MathExamples.cs

src/csharp/Grpc.Examples/MathGrpc.cs

src/csharp/Grpc.Examples/MathServiceImpl.cs

...rp/Grpc.IntegrationTesting/Grpc.IntegrationTesting.csproj

src/csharp/Grpc.IntegrationTesting/InteropClient.cs

...csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs

src/csharp/Grpc.IntegrationTesting/InteropServer.cs

src/csharp/Grpc.IntegrationTesting/TestGrpc.cs

src/csharp/Grpc.IntegrationTesting/TestServiceImpl.cs