INT 7F - Alloy MW386 - SWITCH TO NEW DOS TASK                                   
	AH = E2h
	AL = DOS process number (from AH=E1h)
Return: CF set on error (invalid process number or caller not foreground task)
Notes:	specified task becomes the foreground task and current task is placed
	  in the background
	may only be called by a foreground task
SeeAlso: AH=E0h,AH=E1h