INT 15 U - HP 100LX/200LX - GET/SET DISPLAY CONTRAST                            
	AH = 47h
	AL = subfunction
	   00h set contrast
		BL = new contrast
		    (00h-0Fh, 0Fh is darkest, 10h-FFh are same as 0Fh)
	   other get current contrast
Return: AL = contrast (00h-0Fh, 0Fh is darkest)
Note:	may be for backward compatibility with HP95LX, as INT 15/AH=62h does
	  substantially the same thing as this function
SeeAlso: AH=45h"HP",AH=48h"HP",AH=62h"HP"