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.Editor/Form1.cs

@@ -558,7 +558,7 @@ namespace OpenRA.Editor
 			if (player == null)
 				return;
 
-			var color = player.ColorRamp.GetColor(0);
+			var color = player.Color.RGB;
 			using( var brush = new SolidBrush(color) )
 				e.Graphics.FillRectangle( brush, e.Bounds.Left + 2, e.Bounds.Top + 2, e.Bounds.Height + 6, e.Bounds.Height - 4 );
 			using( var foreBrush = new SolidBrush(e.ForeColor) )