Fix accordion menu toggling
Submenu unread count may be different from reader unread count

- Since submenus may not display all unread items due to max_item limit,
  we should only count the number of unread items shown in the menu when
  displaying a tooltip etc
Fix layout in Cinnamon 2.0.8

- Applet.MenuItem now uses an internal table for layout. This throws the
  whole layout idea of the FeedDisplayItem. We now use a table inside
  this item to make layout a whole lot easier