INT 2F C - NETWORK REDIRECTOR - INSTALLATION CHECK                              
	AX = 1100h
Return: AL = status
	    00h not installed, OK to install
	    01h not installed, not OK to install
	    FFh installed
		AH = product identifier (ad hoc by various manufacturers)
		    00h if PCIBM PC Tools v8 DRIVEMAP
		    42h ('B') for Beame&Whiteside BWNFS v3.0a
		    6Eh ('n') for NetWare Lite v1.1 CLIENT
Notes:	this function is called by the DOS 3.1+ kernel
	in DOS 4.x only, the 11xx calls are all in IFSFUNC.EXE, not in the
	  PCIBM PC LAN Program redirector; DOS 5+ moves the calls back into the
	  redirector
	the PCIBM PC Network 1.00 redirector (renamed to PCIBM PC LAN Program in 1.1-1.3)
	  only supports AL=00h-27h