Merge github.com:grpc/grpc into bye-bye-completion-queue-pie

BUILD

Makefile

build.json

include/grpc/grpc_security.h

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/core/iomgr/endpoint_pair_windows.c

src/core/iomgr/iocp_windows.c

src/core/iomgr/socket_windows.c

src/core/iomgr/socket_windows.h

src/core/iomgr/tcp_client_windows.c

src/core/iomgr/tcp_server_windows.c

src/core/iomgr/tcp_windows.c

src/core/security/auth.c

src/core/security/security_context.c

src/core/security/security_context.h

src/core/surface/call.c