Not Another Dragon Stalking Fix

My own take on the Dragon Stalking Fix.

Notes:

• Important to note: should not ONLY fix the dragon stalking problem, but the problem of this script building up in your save file over time and causing script lag.
  

• Should be safe to install on old saves, but I don't believe it will affect already-loaded dragons in the desired way. For full desired effect, use on a new save.
  

• Script should only activate when the dragon physically loads into the worldspace for the first time.
  

• While the dragon is alive, the relevant script events should only fire while the dragon is loaded in the worldspace.
  

• After the dragon dies, and is unloaded from the worldspace, it should be deleted.
  

• I changed a "While" loop into an "OnUpdate" loop, which should end as soon as the dragon is unloaded.
  

v2: Added automatic compatibility with KS Dragon Overhaul 2 and Dragon War. This version requires SKSE