INT 2F C - MDEBUG display driver - SAVE GRAPHIC DATA                            
	AX = D002h
Return: CF set on error
	CF clear if successful
	    display memory saved and display switched to one of the text modes
	      02h, 03h or 07h.
Note:	MDEBUG calls this function only once every popup session before
	  displaying its windows.
SeeAlso: AX=D000h,AX=D003h