New backend

Since being limited to shared hosting is no longer an issue, and since the internal API is mature enough, we have decided to create a new PostgreSQL-based backend.

One of the main paradigms for our project was to work without a database, but we believe PostgreSQL will do a better work than XML has done.

Still some parts are XML based and will remain so, and from within things look pretty much the same. This will become the default backend in a future release, and a script will be included to move from XML to Postgres shall you decide to do so.

But in the meantime, it's experimental.