Handles an item being dropped onto view, calls
        dropped -- implemented by subclass

def dropEvent(self, event):
        """Handles an item being dropped onto view, calls
        dropped -- implemented by subclass
        """
        super(AbstractDragView, self).dropEvent(event)
        self.dragStartPosition = None
        self.dragline = None
        self.originalPos = None
        data = event.mimeData()
        stream = data.retrieveData("application/x-protocol",
            QtCore.QVariant.ByteArray)
        item = cPickle.loads(str(stream.toByteArray()))

        self.dropped(item, event)

        event.accept()