INT 2F - MDEBUG command driver - GET ADDRESS OF THE OLD INT 2F                  
	AX = D110h
Return: DL = FFh
	ES:BX -> next program in the chain for INT 2F
	CX = code segment of this driver
	DI = offset of driver identification table (see #03079) (v1.60+)
Notes:	only called by the transient part of the driver
	must be reentrant and the driver must not chain this function to the
	  old INT 2F


Format of the MDEBUG driver identification table:
Offset	Size	Description	(Table 03079)
 00h  26 BYTEs	 signature "Kommandotreiber für MDEBUG"
					     ^- Note: ASCII 129,German U-umlaut
 27h  12 BYTEs	 name of driver, e.g. "MDHISDRV.COM"
		 each driver must have a unique name