Goat-notes finalized

[BrassHerbologist]

• [ ] mountain goat will remain the same, minus the additions of the new mechanics
• [ ] same default model in mountains
• [ ] new billygoat model for plains/meadows/hills-type biomes [gravely hills/extreme hills etc]
• [ ] neutral mob that bucks the player back and into the air if provoked
• [ ] eats anything thrown on the ground in front of it
• [ ] can be bred with wheat
• [ ] will sometimes 'play' with other goats, knocking horns together, making a 'clack' sound
• [ ] drops: 1-2 leather, 1-2 mutton
• [ ] spawns: day
• [ ] group size: 2-3

Biomes: is_plains is_mountains is_forest is_desert -no jungle/beach/river