Add a windows version of the launch-game script.

launch-game.cmd

@@ -0,0 +1,24 @@
+@echo off
+title OpenRA
+:choosemod
+set /P mod=Select mod (ra, cnc, d2k, ts) or --exit: 
+if /I "%mod%" EQU "--exit" (exit)
+if /I "%mod%" EQU "ra" (goto launch)
+if /I "%mod%" EQU "cnc" (goto launch)
+if /I "%mod%" EQU "ts" (goto launch)
+if /I "%mod%" EQU "d2k" (goto launch)
+echo.
+echo Unknown mod: %mod%
+echo.
+goto choosemod
+:launch
+OpenRA.Game.exe Game.Mod=%mod%
+if %errorlevel% neq 0 goto crashdialog
+exit
+:crashdialog
+echo ----------------------------------------
+echo OpenRA has encountered a fatal error.
+echo   * Log Files are available in Documents\OpenRA\Logs
+echo   * FAQ is available at https://github.com/OpenRA/OpenRA/wiki/FAQ
+echo ----------------------------------------
+pause