INT E0 - DR Multiuser DOS - "A_WRITE" - WRITE CHARACTER TO DEFAULT AUX DEVICE
	CL = 04h
	DL = BYTE to write
Return: nothing
	may destroy SI,DI,DH???
Note:	if another process owns AUX, this call blocks until the device becomes
	  available
SeeAlso: INT 21/AH=04h,INT E0/CL=03h,INT E0/CL=08h,INT E0/CL=A5h,INT E0/CL=ADh