Merge github.com:grpc/grpc into reject-the-stuffs

Makefile

build.json

include/grpc++/create_channel.h

include/grpc++/credentials.h

src/core/census/grpc_filter.c

src/core/transport/chttp2/stream_lists.c

src/cpp/client/create_channel.cc

src/csharp/Grpc.Core/Metadata.cs

test/core/iomgr/udp_server_test.c

test/core/util/test_config.h

test/cpp/end2end/async_end2end_test.cc

test/cpp/end2end/client_crash_test.cc

test/cpp/end2end/end2end_test.cc

test/cpp/end2end/generic_end2end_test.cc

test/cpp/end2end/mock_test.cc

test/cpp/end2end/server_crash_test_client.cc

test/cpp/end2end/shutdown_test.cc

test/cpp/end2end/thread_stress_test.cc

test/cpp/end2end/zookeeper_test.cc

test/cpp/qps/driver.cc