Amethyst Core 1.2.2+1.19.4

Player Experience is now a living entity attribute, so things like splash potions or modifiers don't crash the game by trying to add a player attribute to a non-player. It still only does anything on players.
Change how cooldown and mana cost attributes work so positive changes reduce duration, and negative modifiers increase duration, to make them more intuitive. Previously a reduction in attribute reduced CD/MC, but it shows as red in MC, implying that you are getting a bad effect.