Ye Olde DOS 3.1

[Lyrical Nanoha <LyricalNanoha@dosius.ath.cx>]

I noticed some interesting and unusual stuff about DOS 3.1...

  * MASTER.CREATE doesn't actually do anything but BRUN RAWDOS.
    The UPDATE 3.2 program is very different from this MASTER.CREATE but
    almost identical to the newer MASTER CREATE from DOS 3.3.
  * RAWDOS has a bizarre side effect: if you catalog the disk after
    running RAWDOS, it will catalog TWICE.
  * Make sure INTBASIC is loaded before trying to BOOT13 DOS 3.1!  The
    master disk will get caught in an infinite loop trying to load HELLO.

-uso.