Layouts should draw all items at once, not once per current layout manager

[arpit]

The draw method on the main TreeMap class draws once the layout managers change. It should really maintain all the layout managers in an internal Array and draw them all at once. This also allows things like redraw without having to compute the rectangles all over again.

public function draw():void{

        var rects:Array = currentLayoutManager.getRects();
        for each(var treeRect:TreeRect in rects){
            var renderer:DisplayObject = new _renderer() as DisplayObject;
            addChild(renderer);
            ITreeMapRenderer(renderer).draw(this, treeRect);
            renderer.x = treeRect.rect.x
            renderer.y = treeRect.rect.y;
        }
    }