API ToggleGameMenu

Opens/closes the game menu.
 ToggleGameMenu()
==Note==
* The that while this function itself is not protected, it calls the following protected functions which trigger the ACTION_BLOCKED event:
**SpellStopCasting()
**SpellStopTargeting()
**ClearTarget()
* The name of this function is a bit of a misnomer, it's actually a handler that fires when the user presses the Escape key.