title: Get item from QListWidget using a QItemSelection or QModelIndex
body: <p>I have a callback in my dialog to listen for item selections in my QListWidget:</p>
  
  <pre><code>...
  QListWidget* listWidget;
  ...
  
  MyDialog::handleSelectionChanged(const QItemSelection&amp; selection) {
      if (selection.indexes().isEmpty()) {
          std::cout &lt;&lt; "NOTHING SELECTED" &lt;&lt; std::endl;
          // TODO: how to get the actual QListWidgetItem here!?
      }
      else {
         bool selected = LoadedFilesListWidget-&gt;selectionModel()-&gt;isSelected(selection.indexes().first());
         std::cout &lt;&lt; "ITEM CHANGE: " &lt;&lt; (selected ? "SELECTED" : "UNSELECTED") &lt;&lt; std::endl;
         // TODO: how to get the actual QListWidgetItem here!?
      }
  }
  </code></pre>
  
  <p>As you can see in the todos, I can't figure out how to get the associated QListWidgetItem from the QItemSelection object.  I have access to the list widget with the <code>listWidget</code> class variable.  Any help is greatly appreciated.</p>