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* Added an optional contexts parameter for the register function, for
providing translation context for model fields.
* Update middleware to the 1.10+ style
* Maintains backwards-compat with 1.9 and below
* Will now work in either ``MIDDLEWARE_CLASSES`` or ``MIDDLEWARE``
* Deprecates ``VinaigrettteAdminLanguageMiddleware`` for ``VinaigretteAdminLanguageMiddleware``
* Users should change to ``vinaigrette.middleware.VinaigretteAdminLanguageMiddleware``
* ``vinaigrette.VinaigrettteAdminLanguageMiddleware`` will continue to work until next major version
* Adds tox and pytest for development and testing