Backend function now only gets called on init hook.
A small fix to prevent the plugin from being loaded too early.
It was giving errors:

Notice: Use of undefined constant TEMPLATEPATH - assumed 'TEMPLATEPATH' in /wp-includes/theme.php on line 131
Notice: Use of undefined constant STYLESHEETPATH - assumed 'STYLESHEETPATH' in /wp-includes/theme.php on line 131
Merge pull request #7 from JvanderHeide/rework

Backend function now only gets called on admin_init hook.