Need QML drag-and-drop support

Currently we have to add a lot of imperative code to do proper drag and drop. It would be good to have a DragTarget element that both knows when items are being dragged over it and then when they are dropped. Say it was a puzzle game. As you drag a puzzle piece around as it goes over several DragTargets they would highlight showing you could drop the piece there. When you let go the piece can slot into place, or be rejected and move back to its original place.