Postgres test floc 1042

If this is suitable, I will add the new dependencies (currently just the latest https://pypi.python.org/pypi/psycopg2) to setup.py. Each dependency must also go in the internal documentation for packages used.

This uses psycopg2 which requires, on OS X for example ``brew install postgresql``. Perhaps it would be better to use http://python.projects.pgfoundry.org, a pure Python implementation. If not, should this just document that you need to install PostgreSQL?.