==================
- Add `IRawReadFile` and `IRawWriteFile` interfaces. These extend
`IReadFile` and `IWritefile`, respectively, to behave pretty much like a
standard Python file object with a few embellishments. This in turn allows
efficient, iterator- based implementations of file reading and writing.
- Remove dependency on ``zope.container``: `IReadDirectory` and
`IWriteDirectory` inherit only from interfaces defined in ``zope.interface``
and ``zope.interface.common.mapping``.