configuration monitor to ease collective administration

 metche monitors changes made to a "system state" composed of:
    - a "watched" directory (typically: /etc)
    - one or more user maintained changelog files
      (e.g. /root/Changelog)
    - the state of Debian packages and versions (using apt-show-versions)
 by periodically:
    - saving backups of the corresponding files
    - emailing the changes in the system state to your administrators'
      mailing list