Replace ColorRamp with HSLColor everywhere.

Fixes:
* Nuclear-purple color exploit.
* #3247.
* Removes a bunch of unnecessary color conversions every frame.

Caveats:
* The ramp range is now defined on the palette, so ramps can no longer be set per-player (may impact maps which define custom colors).
* It's no longer possible to perfectly recreate the original WW color ramps (I doubt we care).
* The old ColorRamp setting isn't migrated, so players will lose their color settings.

OpenRA.Mods.RA/Spy.cs

@@ -117,9 +117,9 @@ namespace OpenRA.Mods.RA
 		{
 			if (!Disguised || self.World.LocalPlayer == null ||
 				self.Owner.Stances[self.World.LocalPlayer] == Stance.Ally)
-				return self.Owner.ColorRamp.GetColor(0);
+				return self.Owner.Color.RGB;
 
-			return disguisedAsPlayer.ColorRamp.GetColor(0);
+			return disguisedAsPlayer.Color.RGB;
 		}
 
 		void DisguiseAs(Actor target)