RSS link update & content

 * Widget apps / update to new link rss.search
 * georss parameter (which control geometry format) should not be considered as a search parameter. Add it to excluded parameter list
 * first item in RSS feed is an empty item (due to summary)
 * change RSS title to the name of the catalog (instead of having always GeoNetwork as title - which is not helpful when you subscribe to many catalogs in your news reader)