Merge github.com:grpc/grpc into test_affine

BUILD

Makefile

binding.gyp

build.yaml

config.m4

examples/cpp/helloworld/Makefile

gRPC.podspec

grpc.gemspec

package.xml

src/core/ext/client_config/subchannel.c

src/core/ext/client_config/subchannel_index.c

...xt/transport/chttp2/client/secure/secure_channel_create.c

...ext/transport/chttp2/server/secure/server_secure_chttp2.c

src/core/ext/transport/chttp2/transport/frame_goaway.c

src/core/ext/transport/chttp2/transport/hpack_parser.c

src/core/lib/channel/channel_args.c

src/core/lib/compression/compression_algorithm.c

src/core/lib/http/httpcli_security_connector.c

src/core/lib/security/context/security_context.c

src/core/lib/security/context/security_context.h