Fix utility to use Platform.SupportDir (#1067); drop the --SupportDir arg and the path passed to --settings-value; Update OSX launcher to match.

OpenRA.Launcher.Mac/main.m

@@ -13,7 +13,7 @@ int main(int argc, char *argv[])
 {
 	/* When launching a mod, the arguments are of the form 
 	 * --launch <game dir> <mono path> <utility path> <support dir option> <mod option> */
-	if (argc >= 7 && strcmp(argv[1], "--launch") == 0)
+	if (argc >= 6 && strcmp(argv[1], "--launch") == 0)
 	{
 		/* Change into the game dir */
 		chdir(argv[3]);
@@ -24,7 +24,6 @@ int main(int argc, char *argv[])
 			"--debug",
 			"OpenRA.Game.exe",
 			argv[5],
-			argv[6],
 			NULL
 		};