Merge remote-tracking branch 'upstream/master' into max_send_size_filter

BUILD

CMakeLists.txt

Makefile

binding.gyp

build.yaml

config.m4

examples/cpp/helloworld/greeter_async_client.cc

examples/cpp/helloworld/greeter_async_client2.cc

examples/cpp/helloworld/greeter_async_server.cc

gRPC-Core.podspec

grpc.gemspec

include/grpc/impl/codegen/atm.h

include/grpc/impl/codegen/atm_gcc_atomic.h

include/grpc/impl/codegen/atm_gcc_sync.h

include/grpc/impl/codegen/atm_windows.h

package.xml

src/core/ext/client_config/client_channel.c

src/core/ext/client_config/subchannel.c

src/core/ext/lb_policy/grpclb/grpclb.c

.../ext/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c