Rekajiggers delayed regeneration on simple animals

Created by: Skullyton

Forces no overlays (Was causing a runtime should the mob not exist, and was immersion breaking), changes it from sleep to spawn (Functionally the same as what I wanted to do, but now not as choppy in theory), undoes redundancy (Resurrect is called in revive() anyway) and now checks to see if the src still exists (Hasn't been butchered, gibbed, incinerated, etc.) before attempting the revive.