Use list selection display options

We can't make one setting depend on another, so we'll just list the
possible combinations.  Closes #7, closes #10.
Add button to request more results

The request is passed back through the query string, so we get an ugly
query.  This also means that departments are inoperative, so we also
pass the department id as part of this query string.  Hopefully
Launchpad #1394480 will give us a better mechanism.