Add (or reset) a few metaData properties as respective fields (if they are
available), so that they can be accurately used within the search index.
'lastModifed' is indexed to support query by date, 'contentLength' obtains
content length from the HTTP header, 'type' field is indexed to support query
by type and finally the 'title' field is an attempt to reset the title if a
content-disposition hint exists. The logic is that such a presence is
indicative that the content provider wants the filename therein to be used as
Still need to make content-length searchable!