Moves spells from mob to mind

- Moves all spells from mob to mind. Construct spells and mime spells are exceptions.
- Spells are transferred whenever a mind is transferred: cloning, pod cloning, borging, staff of changing.
- Spells are not transferred when you create a new mind for a new mob: soul stones, golems, respawns.
- ~~To my surprise, this did not fix the issue where a mind-swapped wizard loses their spells when their original body is destroyed. I do not know why this happens.~~
-  ~~Non-human mobs can't use spells by default. Admins need to change the spell's human_req to 0 if they give spells to non-human mobs.~~