Cleanup registry

Unit tests that change global data should include the CleanUp base class, which provides simpler setUp and tearDown methods that call global-data cleanup routines.

>>> def print_args(*args, **kw):
...     print(args)
...     print(kw)

>>> from zope.testing.cleanup import addCleanUp, CleanUp
>>> addCleanUp(print_args, ('1', 'foo'), {'bar': 42})

CleanUp calls the registered clean up functions on setup and tear down:

>>> CleanUp().setUp()
('1', 'foo')
{'bar': 42}
>>> CleanUp().tearDown()
('1', 'foo')
{'bar': 42}
>>> CleanUp().cleanUp()
('1', 'foo')
{'bar': 42}