Add tox config and gitignore pattern.
Drop permalink decorator in favor of reverse.

Django 1.5 docs recommend this.
Use new location of url functions.
Add support for Django 1.5.
Bump version because of Django 1.5 support.
Add unicode_literals import to all modules.
Drop u prefix on unicode strings.
Decorate models with python_2_unicode_compatible.
Add support for Python 3.3
Bump version because of Python 3 support, Django 1.4.2

Formerly Django 1.4 was the minimum required. Now it is 1.4.2 to
support Python 3 compatibility.