Support arbitrary per-player palettes. Will crash if I missed any cases that don't explicitly set the Renderable palette.

OpenRA.Game/Traits/Util.cs

@@ -98,7 +98,7 @@ namespace OpenRA.Traits
 
 		public static Renderable Centered(Actor self, Sprite s, float2 location)
 		{
-			var pal = self.Owner == null ? "player0" : self.Owner.Palette;
+			var pal = "player{0}".F(self.Owner == null ? 0 : self.Owner.Index);
             var loc = location - 0.5f * s.size;
 
 			return new Renderable(s, loc.Round(), pal, (int)self.CenterLocation.Y);