dont allocate a full new palette texture every frame in HardwarePalette.Update

Author: chrisforbes

OpenRA.Game/Graphics/HardwarePalette.cs

@@ -56,16 +56,16 @@ public void AddPalette(string name, Palette p)
 
 			palettes.Add(name, p);
 			indices.Add(name, allocated++);
-		}
-		
+		}
+
+		uint[,] data = new uint[MaxPalettes, 256];
 		public void Update(IEnumerable<IPaletteModifier> paletteMods)
 		{
 			var copy = palettes.ToDictionary(p => p.Key, p => new Palette(p.Value));
 
 			foreach (var mod in paletteMods)
 				mod.AdjustPalette(copy);
 
-			var data = new uint[MaxPalettes,256];
 			foreach (var pal in copy)
 			{
 				var j = indices[pal.Key];