Description
      Eg, if you pass it pageID = 5 and your delta is 2 it will return you 3 and 7.
      PageID of 6 would give you 4 and 8
     
      NB: The behaviour of this function could be misleading: it was left only
      for compatibility with PEAR::Pager.
      It could raise some confusion when pageID is within delta
      positions from an extreme: in fact this method returns also the extremes, while
      $this->_getPageLinks leaves them out.
      Pager_Sliding works this way: if pageID is NOT an extreme, show first and
      last page within brackets: [1] <<  5 | _6_ | 7  >> [15]
      So when dealing with pageID within delta positions from an extreme,
      this method would return the extreme as well, while $this->_getPageLinks
      would return (for instance) 2 | _3_ | 4 | 5  even if pageID is 3 and delta
      is 2. Consider this method deprecated and/or subject
      to changes.