Revert "add IHasLocation"

This reverts commit 699b4b1154.

OpenRA.Game/Actor.cs

@@ -26,8 +26,7 @@ namespace OpenRA
 		public readonly World World;
 		public readonly uint ActorID;
 
-		public int2 Location { get { return Trait<IOccupySpace>().TopLeft; } }
-		public float2 CenterLocation { get { return Trait<IHasLocation>().PxPosition; } }
+		public int2 Location { get { return Trait<IOccupySpace>().TopLeft; } }
 		[Sync]
 		public Player Owner;
 
@@ -53,6 +52,9 @@ namespace OpenRA
 					AddTrait(trait.Create(init));
 			}
 
+			if( CenterLocation == float2.Zero && HasTrait<IOccupySpace>() )
+				CenterLocation = Traits.Util.CenterOfCell(Location);
+
 			Size = Lazy.New(() =>
 			{
 				var si = Info.Traits.GetOrDefault<SelectableInfo>();
@@ -97,6 +99,8 @@ namespace OpenRA
 			get { return currentActivity == null || currentActivity is Idle; }
 		}
 
+		public float2 CenterLocation;
+
         OpenRA.FileFormats.Lazy<float2> Size;
 
 		public IEnumerable<Renderable> Render()