title: QTreeView with drag and drop support in PyQt
body: <p>In PyQt 4 I would like to create a QTreeView with possibility to reorganize its structure with drag and drop manipulation.</p>
  
  <p>I have implemented my own model(QAbstractItemModel) for QTreeView so my QTreeView properly displays the data.
  Now I would like to add drag and drop support for tree's nodes to be able to move a node inside the tree from one parent to another one, drag-copy and so on, but I cannot find any complete tutorial how to achieve this. I have found few tutorials and hints for QTreeWidget, but not for QTreeView with custom model.
  Can someone point me where to look?</p>
  
  <p>Thank you.</p>