Update Django version to 1.6.x.

These changes are based on [pull request #26](https://github.com/openshift/django-example/pull/26), by @suhailvs. I have attempted to strip out all non-essential changes that @suhailvs made (e.g., moving files to a new directory, renaming the SQLite database file, updating to Python 2.7, etc.), leaving only the minimal amount of changes required to update to Django 1.6.x.

Tested with Django 1.6.2 on a Python 2.6 cartridge.