Merge github.com:grpc/grpc into all-the-small-things

Makefile

build.json

include/grpc/grpc.h

include/grpc/support/port_platform.h

src/core/iomgr/socket_utils_common_posix.c

src/core/iomgr/socket_utils_posix.h

src/core/iomgr/tcp_client_posix.c

src/core/iomgr/tcp_posix.c

src/core/iomgr/tcp_server_posix.c

src/core/surface/call.c

src/core/transport/chttp2_transport.c

src/core/transport/metadata.c

src/core/transport/metadata.h

src/cpp/server/server.cc

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

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

src/csharp/Grpc.Core/AsyncClientStreamingCall.cs

src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs

src/csharp/Grpc.Core/AsyncServerStreamingCall.cs

src/csharp/Grpc.Core/Call.cs