Allow to add panels full width

[vshcherb]

1. Plus rename class to ButtonPositionSize -> WidgetPositionSize

2. Create unit test for this case

   
   public static void main(String[] args) {
       List<ButtonPositionSize> lst = defaultLayoutExample();
       for (ButtonPositionSize b : lst) {
           System.out.println(b);
       }
       System.out.println("--------");
       ButtonPositionSize.computeNonOverlap(0, lst);
       for (ButtonPositionSize b : lst) {
           System.out.println(b);
       }   
   }
   
   public static List<ButtonPositionSize> defaultLayoutExample() {
       List<ButtonPositionSize> lst = new ArrayList<ButtonPositionSize>();
       lst.add(new ButtonPositionSize("topPanel", 7, ButtonPositionSize.POS_FULL_WIDTH, ButtonPositionSize.POS_TOP).
               setMoveDescendantsVertical());
   
       lst.add(new ButtonPositionSize("leftWid", 7, ButtonPositionSize.POS_LEFT, ButtonPositionSize.POS_TOP).
               setMoveDescendantsVertical().setSize(10, 10));
   
       lst.add(new ButtonPositionSize("zoomOut", 7, false, false).setMoveVertical());
       lst.add(new ButtonPositionSize("zoomIn", 7, false, false).setMoveVertical());
       lst.add(new ButtonPositionSize("myLoc", 7, false, false).setMoveHorizontal());
   
       lst.add(new ButtonPositionSize("drawer", 7, true, false).setMoveHorizontal());
       lst.add(new ButtonPositionSize("navigation", 7, true, false).setMoveHorizontal());
       lst.add(new ButtonPositionSize("ruler", 10, true, false).setMoveHorizontal());
   
       lst.add(new ButtonPositionSize("configMap", 6, true, true).setMoveHorizontal());
       lst.add(new ButtonPositionSize("search", 6, true, true).setMoveHorizontal());
       lst.add(new ButtonPositionSize("compass", 6, true, true).setMoveVertical());
       return lst;
   }