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
Hmm fair point. :+1: 
It's already in the `is_admin()` if statement, so based on that it shouldn't even be needed, but i do agree `admin_init` would suit it better.
 
The `!is_admin()` in the function was more of a check to make sure someone didn't call it form the frontend. Keep or go, what would you say?