Monkey forms for skeletons, plasmamen and greys, vox monkey form improved

Created by: Skullyton

Fixes #6767 (closed) fixes #8403 (closed)

With sprites provided by Niggly and splicing existing sprites, 3 new monkey forms (Skeleton, Plasmaman, and Grey) are added.

Skeleton monkey forms are skulls that hop when they move

Plasmamen monkey forms are flaming hopping skulls

Grey monkey forms are big-headed monkey things

Also, fixes vox chickens a little

Now only have 1 hand slot, their beak Methylin means something now, letting them pick things up There's a proper check for amount of eggs left, whereas previously there was not Vox chickens now lay eggs if they're idle or not