Merge github.com:grpc/grpc into forever-is-a-long-time

BUILD

Makefile

build.json

gRPC.podspec

include/grpc/grpc.h

include/grpc/support/slice_buffer.h

src/core/channel/client_channel.c

src/core/channel/http_client_filter.c

src/core/channel/http_server_filter.c

src/core/iomgr/iomgr.h

src/core/security/security_connector.c

src/core/security/security_context.c

src/core/security/security_context.h

src/core/security/server_auth_filter.c

src/core/support/slice_buffer.c

src/core/surface/call.c

src/core/surface/lame_client.c

src/core/surface/server.c

src/core/transport/chttp2/alpn.h

src/core/transport/chttp2/bin_encoder.c