Remove unnecessary int2 -> PPos -> int2 conversions.

OpenRA.Game/Traits/World/ScreenMap.cs

@@ -127,9 +127,6 @@ namespace OpenRA.Traits
 				.Select(kv => kv.Key);
 		}
 
-		// Legacy fallback
-		public IEnumerable<Actor> ActorsAt(PPos pxPos) { return ActorsAt(pxPos.ToInt2()); }
-
 		public IEnumerable<Actor> ActorsInBox(int2 a, int2 b)
 		{
 			return ActorsInBox(Rectangle.FromLTRB(Math.Min(a.X, b.X), Math.Min(a.Y, b.Y), Math.Max(a.X, b.X), Math.Max(a.Y, b.Y)));