Merge github.com:grpc/grpc into direct-calls

BUILD

CMakeLists.txt

Makefile

binding.gyp

build.yaml

config.m4

doc/core/pending_api_cleanups.md

gRPC-Core.podspec

grpc.gemspec

include/grpc++/ext/reflection.grpc.pb.h

include/grpc++/ext/reflection.pb.h

include/grpc/impl/codegen/grpc_types.h

package.xml

src/core/ext/client_config/client_channel.c

src/core/ext/client_config/lb_policy.c

src/core/ext/client_config/lb_policy.h

src/core/ext/client_config/subchannel.c

src/core/ext/client_config/subchannel.h

src/core/ext/client_config/subchannel_factory.c

src/core/ext/client_config/subchannel_factory.h