Prettier Horses x Fresh Animations

-fixed baby models

-fixed donkey and mule chests appearing permanently

-fixed horse saddles floating/duplicating on horse model

-fixed horse armor animations not working

-fixed floating zombie horses, skeleton horses, donkeys and mules

-small adjustments to horse textures 

-added wither skeleton horse (nametag "wither")

-fixed baby horse legs being invisible or floating

-fixed unicorn variants not spawning in dark forests

-fixed axis fighting errors