ClassIcons: Addresses enable/disable bug, when player respecs.
For example, if we login as shadow priest, produce few orbs, then respec to holy, then respec back to shadow, we won't have our shard bar back.
We'd better have PLAYER_TALENT_UPDATE event being always registered for priests and warlocks.
Added a call of Path function on disable inside of Visibility function, just in case some needs to perform something via PostUpdate function right after we hid classicons.
Few minor tweaks.