bib is removed from smudge on building death

OpenRa.Game/Traits/TraitsInterfaces.cs

@@ -10,4 +10,5 @@ namespace OpenRa.Game.Traits
 	interface ITick { void Tick(Actor self); }
 	interface IRender { IEnumerable<Pair<Sprite, float2>> Render(Actor self); }
 	interface IOrder { Order Order(Actor self, int2 xy, bool lmb, Actor underCursor); }
+	interface INotifyRemoved { void Removed(Actor self); }
 }