Add support for launching the game.

OpenRA.Launcher.Mac/OpenRA.app/Contents/MacOS/OpenRA

@@ -0,0 +1,10 @@
+#!/bin/bash
+# Copyright 2007-2010 The OpenRA Developers (see AUTHORS)
+# This file is part of OpenRA, which is free software. It is made 
+# available to you under the terms of the GNU General Public License
+# as published by the Free Software Foundation. For more information,
+# see LICENSE.
+
+echo "Launching OpenRA from $1"
+cd $1
+${@:2}