INT 2F - METZ XpressFax CASMGR - INSTALLATION CHECK                             
	AX = CB00h
	BX = 4D53h ('MS')
	CX = 4949h ('II')
Return: AL = status
	    00h not installed, OK to install
	    01h not installed, not OK to install
	    FFh installed
		BX = 6D73h ('ms')
		CX = 6969h ('ii')
Note:	this function is equivalent to the standard CASMGR installation check,
	  but uses the additional magic values to identify which CASsee Communicating Applications Specification is
	  installed
SeeAlso: AH=2Ah,AX=8000h"FaxBIOS",AX=C000h/BX=444Bh,AX=CB0Eh,AX=CB16h