Add guessit dependancy stevedore

lib/stevedore/__init__.py

lib/stevedore/dispatch.py

lib/stevedore/driver.py

lib/stevedore/enabled.py

lib/stevedore/example/__init__.py

lib/stevedore/example/base.py

lib/stevedore/example/fields.py

lib/stevedore/example/load_as_driver.py

lib/stevedore/example/load_as_extension.py

lib/stevedore/example/setup.py

lib/stevedore/example/simple.py

lib/stevedore/extension.py

lib/stevedore/hook.py

lib/stevedore/named.py

lib/stevedore/sphinxext.py

lib/stevedore/tests/__init__.py

lib/stevedore/tests/extension_unimportable.py

lib/stevedore/tests/manager.py

lib/stevedore/tests/test_callback.py

lib/stevedore/tests/test_dispatch.py