INT 2F - REDVIEW - INSTALLATION CHECK
        AX = BE00h
Return: AL = FFh if installed
Note:   REDVIEW is a public-domain TSR by Alexandr Novy and Petr Horak which
          copies data sent to standard output to standard error when the
          former has been redirected to a file, thus allowing the data to
          be seen on the screen at the same time it is captured in a file