migrate url tags to Django 1.5

This pull request is for migration from old url tag format to Django 1.5 url tag format.

I used [django-future-url](https://github.com/futurecolors/django-future-url) and I have passed all the built-in tests in pybbm.
(Because it seems [original django-registration](https://bitbucket.org/ubernostrum/django-registration) has been broken for a long time, I used [a fork of django-registration](https://bitbucket.org/jscott1971/django-registration/commits/all/tip/branch%28%22cbv%22%29))