INT 29 - DOS 2+ - FAST CONSOLE OUTPUT
        AL = character to display
Return: nothing
Notes:  automatically called when writing to a device with bit 4 of its device
          driver header set (see also INT 21/AH=52h)
        COMMAND.COM v3.2 and v3.3 compare the INT 29 vector against the INT 20
          vector and assume that ANSI.SYS is installed if the segment is larger
        the default handler under DOS 2.x and 3.x simply calls INT 10/AH=0Eh
        the default handler under DESQview 2.2 understands the <Esc>[2J
          screen-clearing sequence, calls INT 10/AH=0Eh for all others