Rename urls to match Django >= 1.6

Django 1.4 added names to `contrib.auth.urls`. Django 1.6 started using the url names in views.  

This PR updates the urls to use the same names as Django.

In addition Django 1.6 updated `password_reset_confirm` view / url parameter changed from `uidb36` to `uidb64`. The old `uidb36` version is still available in Django for backwards compatibility.