Added code to load defaults settings from config.xml

On a fresh install, the params from the config.xml were not loaded. As a consequence, the enable_css was not set and thus the k2.css was not loaded on the front-end. 

Just opening and savind the k2 configuration parameters worked as a work around. The solution is to extract the default parameters from the config.xml file and store these in the database.

This issue is potentially related to bug #2. I've asked for some more details to confirm.

Cheers, Paul