code: private String parseHeadline(VTDNav vn) throws NavException {
          require (vn.matchElement(AgigaConstants.DOC));        
          if (!vn.toElement(VTDNav.FIRST_CHILD, AgigaConstants.HEADLINE) || vn.getText() == -1) {
              // If there is no headline annotation return the empty list
              log.finer("No headline found");
              return null;
          }
          return vn.toString(vn.getText()).trim();
      }
docs: Parses out the HEADLINE element, which is a parse of the dateline if it exists.
  
  Assumes the position of vn is at a "DOC" tag