Add IMove interface.

Fixes Rallypoints for aircraft.
Add Order.ExtraData field.
Add ITargetableInfo interface for querying target types.
Change WeaponInfo.EffectivenessAgainst to take ActorInfo.
Introduce Target.Type property.
Merge IOrderTargeter.CanTargetActor and CanTargetLocation.
Allow world and (render-) player actors to render.
Track per-player frozen actors.
Show tooltips for frozen actors.
Allow frozen actors to be flashed.
Add FrozenActor target type.
Add plumbing for issuing orders against frozen actors.
Add helper for resolving orders against frozen actors.
Enable frozen order: Attack.
Enable frozen order: DeliverSupplies.