owl mode

This is an owl-themed mod. It adds friendly owl mobs, a boss owl, called the withered owl, and it adds an owl biomes that contains owl blocks and amethyst trees. It also introduces a fluid called slushi and a recipe for an owl hammer that requires copper! There is also a portal to owl land but it will cause a lot of LAG.  Make sure to use the new projectile feathers and they are strong, but be careful, the withered owl also uses them! Have fun!