Ability to maintain two seperate lists of busts added with a third "forced override option".

Busts in classes.resources.busts.OverrideBusts will always be used.
Otherwise, any bust present in EITHER classes.resources.busts.GatsBusts OR ChesireBusts will be used.
It's setup so that Chesire or Gats can be given priority. It can then be further configured to enable or disable fallbacks. Ie, give preference to Gats and disable fallbacks - you will only see Gats' busts and never see chesires.
There's also a toggle to completely disable busts.

Need to wire up some kind of Options UI to this stuff now.