Merge branch 'master' into ruby_garbage_collection_fixes

.travis.yml

...mple.xcodeproj/xcshareddata/xcschemes/AuthSample.xcscheme

...orld.xcodeproj/xcshareddata/xcschemes/HelloWorld.xcscheme

...codeproj/xcshareddata/xcschemes/RouteGuideClient.xcscheme

setup.py

src/core/lib/iomgr/ev_epoll_linux.c

...e/Sample.xcodeproj/xcshareddata/xcschemes/Sample.xcscheme

...ple.xcodeproj/xcshareddata/xcschemes/SwiftSample.xcscheme

src/objective-c/tests/InteropTests.m

src/python/grpcio/grpc/_cython/cygrpc.pyx

src/python/grpcio/tests/tests.json

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

tools/run_tests/run_tests.py