Merge pull request #993 from nathanielmanistaatgoogle/framework-cleanup

src/python/src/grpc/_adapter/fore.py

src/python/src/grpc/_adapter/rear.py

src/python/src/grpc/early_adopter/_reexport.py

src/python/src/grpc/early_adopter/implementations.py

src/python/src/grpc/framework/assembly/__init__.py

src/python/src/grpc/framework/assembly/implementations.py

...ython/src/grpc/framework/assembly/implementations_test.py

src/python/src/grpc/framework/assembly/interfaces.py

src/python/src/grpc/framework/face/implementations.py

src/python/src/setup.py

tools/run_tests/python_tests.json