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

BUILD

Makefile

README.md

build.json

doc/interop-test-descriptions.md

include/grpc++/auth_context.h

include/grpc++/auth_property_iterator.h

include/grpc++/completion_queue.h

include/grpc++/fixed_size_thread_pool.h

include/grpc++/server_context.h

include/grpc++/thread_pool_interface.h

include/grpc/support/time.h

include/grpc/support/useful.h

src/compiler/csharp_generator.cc

src/compiler/objective_c_generator.cc

src/core/channel/client_channel.c

src/core/client_config/lb_policies/pick_first.h

src/core/client_config/subchannel.c

src/core/client_config/uri_parser.c

src/core/httpcli/httpcli.c