INT 49 - TI Professional PCIBM PC - CRT - WRITE BLOCK OF CHARACTERS WITH ATTRIBUTE
	AH = 10h
	AL = attribute (becomes new current attribute)
	DX:BX -> string of characters to write
	CX = length of string
Return: nothing
Note:	AH=00h,04h,05h,0Bh,0Ch,0Dh,0Fh are documented as NOPs
BUG:	CX must not be 0000h on entry, or the system will crash
SeeAlso: AH=01h,AH=02h,AH=09h,AH=0Eh,AH=11h