title: Need QGraphicsScene signal or event for _after_ change
body: <p>I use <code>QGraphicsScene</code> of the Qt framework. Inside the scene I have some <code>QGraphicsItem</code>s which the user can select and move.
  I would like to have an info label where the current x and y coordinate of the currently moved selection (can consist of many items) is displayed.</p>
  
  <p>I have tried with the signal <code>changed</code> of <code>QGraphicsScene</code>. But it is fired <em>before</em> the x() and y() property of the items is set to the new values. So the labels always show the second-to-last coordinates. If one moves the mouse slowly, the display is not very wrong. But with fast moves and sudden stops, the labels are wrong. I need a signal that is fired <em>after</em> the scene hast changed.</p>
  
  <p>I have also tried to override the <code>itemChange</code> method of <code>QGraphicsItem</code>. But it is the same. It is fired <em>before</em> the change. (The new coordinates are inside the parameters of this method, but I need the new coordinates of all selected items at once)</p>
  
  <p>I have also tried to override the <code>mouseMove</code> events of <code>QGraphicsScene</code> and of <code>QGraphicsView</code> but they, too, are <em>before</em> the new coordinates are set.</p>
  
  <p>I did a test: I used a oneshot timer so that the labels are updated 100 ms after the signals. Then everything works fine. But a timer is no solution for me.</p>
  
  <p>What can I do?
  Make all items un-moveable and handle everything by my own?</p>