INT 13 - SyQuest - DOOR LATCH/DOOR BUTTON DETECT                                
	AH = 1Fh
	AL = subfunction
	    00h allow media removal
	    01h prevent media removal (lock door)
	DL = drive ID (bit 7 set for hard disks)
Return: CF clear if successful
	    AH = 00h
	CF set on error
	    AH = error code
		00h successful
		01h invalid function request
		80h timeout
		DDh media change requested
SeeAlso: AH=12h"SyQuest",AH=13h"SyQuest",AH=59h"SyQuest"