* Adds support for linking Armor traits to HitShapes.
* Adds spread support to TargetDamageWarhead
* Removes ring-damage support from HealthPercentageDamage
* Removes IsValidAgainst check from DoImpact(Actor victim...) overload
and instead lets warheads perform the check beforehand
(to avoid HitShape look-ups on invalid targets).
* Reduces duplication and improves readability of Warhead implementations
And remove ITargetablePositions from Building.
Also, added UseFootprintOffsets to replicate the old Building behavior for easier setup of TargetablePositions for buildings.
