Remove System.Bitmap from badge and mod icons.

OpenRA.Game/Exts.cs

@@ -450,25 +450,6 @@ namespace OpenRA
 
 		public static Rectangle Bounds(this Bitmap b) { return new Rectangle(0, 0, b.Width, b.Height); }
 
-		public static Bitmap CloneWith32bbpArgbPixelFormat(this Bitmap original)
-		{
-			// Note: We would use original.Clone(original.Bounds(), PixelFormat.Format32bppArgb)
-			// but this doesn't work on mono.
-			var clone = new Bitmap(original.Width, original.Height, PixelFormat.Format32bppArgb);
-			try
-			{
-				using (var g = System.Drawing.Graphics.FromImage(clone))
-					g.DrawImage(original, original.Bounds());
-			}
-			catch (Exception)
-			{
-				clone.Dispose();
-				throw;
-			}
-
-			return clone;
-		}
-
 		public static int ToBits(this IEnumerable<bool> bits)
 		{
 			var i = 0;