Not searching assigned persons for hidden projects
Added last_modified field to project/person for nicer search index updating
Using 'last_modified' field for filter updates
Added dateutil, haystack needs it for its update mechanism
last_modified needs to be auto_now instead of auto_now_add
Prepared 'archived' as possible facet, but more work needs to be done here.
Beautified the result list
Simplified the form a bit