Merge github.com:grpc/grpc into flow-like-lava-to-a-barnyard

.gitignore

doc/connection-backoff.md

include/grpc++/impl/call.h

include/grpc/support/port_platform.h

src/compiler/objective_c_generator.cc

src/core/iomgr/socket_windows.c

src/core/iomgr/tcp_server_windows.c

src/core/transport/chttp2/frame_data.c

src/csharp/Grpc.Auth/Grpc.Auth.csproj

src/csharp/Grpc.Auth/Grpc.Auth.nuspec

src/csharp/Grpc.Auth/Properties/AssemblyInfo.cs

src/csharp/Grpc.Core.Tests/ClientServerTest.cs

src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj

src/csharp/Grpc.Core.Tests/GrpcEnvironmentTest.cs

src/csharp/Grpc.Core.Tests/PInvokeTest.cs

src/csharp/Grpc.Core.Tests/Properties/AssemblyInfo.cs

src/csharp/Grpc.Core.Tests/ServerTest.cs

src/csharp/Grpc.Core/Calls.cs

src/csharp/Grpc.Core/Channel.cs

src/csharp/Grpc.Core/Grpc.Core.csproj