Merge remote-tracking branch 'upstream/master' into handshake_api2

.gitignore

Makefile

build.yaml

composer.json

doc/command_line_tool.md

grpc.def

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

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

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

include/grpc/impl/codegen/slice.h

package.xml

...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

src/php/composer.json

src/php/tests/interop/interop_client.php

src/ruby/ext/grpc/rb_grpc_imports.generated.c