INT 10 - VIDEO - TOGGLE INTENSITY/BLINKING BIT (Jr, PS, TANDY 1000, EGA, VGA)

	AX = 1003h
	BL = new state
	    00h background intensity enabled
	    01h blink enabled
	BH = 00h to avoid problems on some adapters
Return: nothing
Notes:	although there is no function to get the current status on adapters
	  prior to the VGA, bit 5 of 0040h:0065h indicates the state; on the
	  VGA, use AH=1Bh and check offset 2Dh of the returned data (see #00040)
	when configured for a monochrome display, the Boca Research Multi-EGA
	  with ROM v M1.1 Type D has its screen disrupted if BH is not clear
	this call is reported to be "Get Cursor Position" on the Tandy
	  1000SL/TL
SeeAlso: AH=08h,AH=1Bh