Merge github.com:grpc/grpc into grand-unified-closures

.gitignore

Makefile

build.yaml

composer.json

doc/command_line_tool.md

doc/images/load_balancing_design.png

doc/load-balancing.md

gRPC-Core.podspec

grpc.def

include/grpc++/impl/codegen/client_context.h

include/grpc++/impl/codegen/config_protobuf.h

include/grpc/impl/codegen/slice.h

package.xml

src/core/ext/client_config/channel_connectivity.c

...core/ext/transport/chttp2/server/insecure/server_chttp2.c

...ext/transport/chttp2/server/secure/server_secure_chttp2.c

src/core/lib/iomgr/tcp_server.h

src/core/lib/iomgr/tcp_server_posix.c

src/core/lib/iomgr/tcp_server_windows.c

src/core/lib/support/slice.c