Cloning for WidgyPages

Puts a 'Clone' button on the widgy mezzanine WidgyPage admin (next to 'View on site'). Clicking it will ask you for a new title and create a new page with a cloned version of the widgy content, including the
working copy and history.

Cloning of the VersionTracker itself is done through its new `clone` method.
yes, it's documented. https://docs.djangoproject.com/en/1.6/ref/urls/#django.conf.urls.patterns. `patterns()` is being deprecated in 1.8 in fact.