Replace django-social-auth with python-social-auth
Remove unused UUIDField
Convert to Python 3 compatible code using 2to3
travis-ci: Use PostgreSQL 9.3 and PostGIS 2.1
travis-ci: Use precompiled Python's psycopg2 and lxml
travis-ci: Update PostGIS script
travis-ci: Set PYTHONPATH
travis-ci: Use Python 3.3
travis-ci: Compile Python 3's psycopg2 and lxml