INT 10 - VIDEO - WRITE GRAPHICS PIXEL

	AH = 0Ch
	BH = page number
	AL = pixel color
	    if bit 7 set, value is XOR'ed onto screen except in 256-color modes
	CX = column
	DX = row
Return: nothing
Desc:	set a single pixel on the display in graphics modes
Notes:	valid only in graphics modes
	BH is ignored if the current video mode supports only one page
SeeAlso: AH=0Dh,AH=46h