Added a trait that removes an actor when prereqs are met, with delay.

It is quite useful if you want a switch upgrade.
An example would be to upgrade rifleman to use bazookas, that unlocks an upgrade to revert them back to rifles, when that is researched it kills the actor that had the other prereqs so you don`t have both at once.

Its also quite funny to see all your powerplants explode when you build a barracks.
Good point self.Info.Name might be good enough, might need something else too though.

I imagine this will break in both cases though if I have two of these traits on the same actor.