UniversalBar

Performance improvements:

* Skip processing a slot when loading saved configuration if the intended action is already in that slot

* Loading more than one action bar no longer produces several seconds of client latency. Loading bars is slightly slower but it should be far less problematic

Bug fix:

* Shared bars that are enabled through the addon aren't actually setting the action bar enable state. Blizzard doesn't have a great way of fixing this in their settings panel without a /reload, but we do at least now set the correct intended state.