TODO
====

* Should the cookie be expired when visiting an item outside the
  cookie results?  Consider the case where such an item is contained
  by a folder with next/prev enabled.  As it currently stands, the
  next/prev links won't be rendered on this item.  Not sure if it
  would be better or worse to have viewing an item outside the result
  set clear the cookie.

* Add the cookie expiration to all other listing views:
  folder_contents, atct_album_view

* Add coverage for viewing one topic listing after another, when both
  topics have next/prev enabled and when only one does
