This model class wraps Search::Xapian to provide a friendly, paged
interface to Xapian (www.xapian.org) indexes. This class adds a little
extra convenience on top of the Search::Xapian class. It expects you to
use the QueryParser, and sets up some keywords based on the standard
omega keywords (id, host, date, month, year,title), so that you can do
searches like

      'fubar site:microsoft.com'