[bug-mailutils] POP3 code changes

[Alain Magloire]

- It is very very cool to have [bug-mailutils] in the header
  now can identify mail by just a glance and get to the urgent.
  Thanks jeff =8)

-  hum ... can we change the Reply-To header to be address@hidden too?

- Anybody working on the POP3 code ?  May find some free time to work a little
  on this:
   * The idea was to separate the framework (mailbox_t etc ..) from
     the implementation, so for example having POP3 code accessible 
     outside of mailbox_t etc .. so the header could be in
     mailutils/sys/pop3.h

   * Not sure about the MH code, but if it was(clear separation) the
     Maildir stuff could be made easier.