Merge branch 'cq_factory_api' into cq_create_api_changes_with_factory

CMakeLists.txt

Makefile

binding.gyp

build.yaml

config.m4

gRPC-Core.podspec

grpc.def

grpc.gemspec

include/grpc/grpc.h

package.xml

src/core/lib/surface/completion_queue_factory.c

src/core/lib/surface/completion_queue_factory.h

src/python/grpcio/grpc_core_dependencies.py

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

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

tools/doxygen/Doxyfile.core.internal

tools/run_tests/generated/sources_and_headers.json

vsprojects/vcxproj/grpc/grpc.vcxproj

vsprojects/vcxproj/grpc/grpc.vcxproj.filters

vsprojects/vcxproj/grpc_test_util/grpc_test_util.vcxproj