Upgrade to precise32 from lucid32
Apply miscellaneous upgrades

* Call python2.7 instead of python2.6
* Read Python from requirements/{dev,prod}.txt
* Add $DATABASE_URL to .profile (to support dj-database-url:
  https://github.com/kennethreitz/dj-database-url)
* Update PostgreSQL Role/DB creation syntax
* Import SQL file containing merely a comment