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

src/core/lib/iomgr/endpoint.h

src/core/lib/iomgr/ev_poll_and_epoll_posix.c

src/core/lib/iomgr/ev_poll_posix.c

src/core/lib/iomgr/ev_posix.c

src/core/lib/iomgr/ev_posix.h

src/core/lib/iomgr/tcp_posix.c

src/php/bin/stress_client.sh

src/php/tests/interop/interop_client.php

src/php/tests/interop/messages.proto

src/php/tests/interop/stress_client.php

src/php/tests/interop/test.proto

src/python/grpcio/grpc/__init__.py

src/python/grpcio/grpc/_adapter/_types.py

src/python/grpcio/grpc/_common.py

src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi

src/python/grpcio/grpc/beta/interfaces.py

src/python/grpcio/tests/tests.json

src/python/grpcio/tests/unit/_api_test.py

...thon/grpcio/tests/unit/beta/_connectivity_channel_test.py

templates/tools/dockerfile/run_tests_addons.include