------------
to implement
------------

* RESTORE: This will purge all packages currently installed but not listed
  in the named snapshot, and perhaps it also installs any packages
  listed in the snapshot but not currently installed

* UPGRADE-VERSION: this would upgrade every package at the first version
  level to that of the second version.
  $ wajig upgrade-version 4.3.0.dfsg.1-6 4.3.0.dfsg.1-8

* Add GJIG to GNOME menu, under System->Administration

* If command expects arguments then instead of error, give a text box
  to enter the arguments, then add it to the Packages text box.

* TOUPGRADE: should show all packages that are newer in unstable, even if
  a pin is set



-----------
to consider
-----------

* use /var/log/dpkg.log for the log instead of our own

* rewrite: the code has evolved to a state where it would be best to
  redesign it properly, object-oriented

* start using grep-dctrl more

* have an option where netselect-apt directly places the
  results into /etc/apt/sources.list?
