* gnus-win.el (gnus-configure-windows-hook): New hook.

* gnus-win.el (gnus-configure-windows): Minimize tree buffer.

* gnus-sum.el (gnus-update-marks): Don't uncompress the seen
lists.
(gnus-select-newsgroup): Don't append; push.
(gnus-adjust-marked-articles): Remove obsolete ranges from
`seen'.
(gnus-update-marks): Clean up.
(gnus-select-newsgroup): Don't stomp gnus-newsgroup-seen.

* gnus-sum.el (gnus-summary-limit-to-age): Allow negative days.