Correctly recompute the actor when something changes that could modify
it (ownership change, ...).
Make sure mirages are updated when they reappear after being hidden.
Make sure foundations have proper identity classes.
Make sure mirages don't respond to value modifications in the visual
component.
Clarify a few comments.
Earlier work by: Sandarac
Fixes#2907
Differential Revision: https://code.wildfiregames.com/D576
This was SVN commit r24279.
wraitii
7bf933d5f6