INT 13,16 - Change of Disk Status (XT BIOS from 1/10/86 & newer)

	AH = 16h
	DL = drive number (0=A:, 1=2nd floppy, 80h=drive 0, 81h=drive 1)


	on return:
	AH = 00 no disk change
	   = 01 disk changed
	CF = set if disk has been removed or an error occurred


	- used to detect if a disk change has occurred
	- see	INT 13,STATUS    INT 13,15