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- LP 811792: work around buggy behavior in some subclasses of
``zope.interface.interface.InterfaceClass``, which invoke ``__hash__``
before initializing ``__module__`` and ``__name__``. The workaround
returns a fixed constant hash in such cases, and issues a ``UserWarning``.
- LP 804832: Under PyPy, ``zope.interface`` should not build its C
extension. Also, prevent attempting to build it under Jython.
- Add a tox.ini for easier xplatform testing.
- Fix testing deprecation warnings issued when tested under Py3K.