Bukkit

Maintenance update for 1.12

- added new creatures: "Cave_Spider", "Donkey", "Elder_Guardian", "Evoker", "Guardian", "Husk", "Illusioner", "Llama", "Mule", "Parrot", "Polar_Bear", "Rabbit", "Shulker", "Skeleton_Horse", "Snowman", "Stray", "Vex", "Vindicator", "Zombie_Horse", "Zombie_Villager"

- fixed arrow errors

- fixed metrics errors