Include Django 1.6 beta for testing
Try fixing matrix exclusions

Only test with Django 1.4 on Python 2.x and only test with Django 1.6b on
Python 2.7.x and above.
Use str representation for Python3 compatability
Fixes old URL confs namespacing
Remove stray `django.conf.urls.defaults` import
Adds build status and PyPI version to README

[ci skip]