Mutation fixes

OK. This fixes the assorted mutation-issues people have been filing, and should make THRESH_URSINE a bit more achievable by breaking out BEAR_EYE, making a PAWS_LARGE (PAWS_BEAR would be post-thresh), and moving Shaggy Fur as a direct-from Lightly rather than requiring Furry first.

It lost the first commit I made.  Thinking that somehow got mixed in with a build-fix a few days ago, so #7356 should already be fixed.  To be totally clear: mistake on my part, I'd guess.  Not sure what happened, would swear that I'd changed branches appropriately, but apparently it's made but not in this one.  *shrug*