Merge branch 'master' of github.com:grpc/grpc into cq_alarm

BUILD

binding.gyp

build.yaml

gRPC.podspec

grpc.gyp

include/grpc/support/port_platform.h

package.json

src/core/channel/client_channel.c

src/core/channel/compress_filter.c

src/core/client_config/subchannel.c

src/core/client_config/subchannel.h

src/core/client_config/uri_parser.c

src/core/httpcli/parser.c

src/core/iomgr/fd_posix.c

src/core/iomgr/tcp_client_posix.c

src/core/iomgr/tcp_server_posix.c

src/core/security/credentials.c

src/core/security/credentials.h

src/core/security/security_context.c

src/core/security/security_context.h