A RedirectFallbackMiddleware that works with Mezzanine

CommonMiddleware and Mezzanine's urlpatterns don't interact well. Mezzanine has a url for '.*/', so CommonMiddleware tries to redirect every no-slash request to the slash version. This means that RedirectFallbackMiddleware wouldn't check for redirects, because it's not a 404.

We should still check for a redirect if this response is due to CommonMiddleware.

Is Widgy the right place for these middlewares? The GenericTemplateFinder one has been in widgy for a while.