THINGS TO DO:

1.  Control.
    - Return address checking for security.
    - Implement all other control messages as well.

2.  Lock the history file when we are messing with it (!).
    Locking is generally a big mess. :-(

3.  Generate the Xref: header. 's gonna be a big problem.

4.  What about a newsspool spread over several partitions?
