Brought in code from DraggableCollectionView. Commiting before trying some experiements.
Sample 3 under development. Integrated code from DraggableCollectionView. Starting to work.
Merge from master.
Drag shadow is no longer centered on the touch, but rather offset to the original touch point.
Updates to lifecycle to include dragStarted when shouldDragStart returns true. Cleanup.
Updates to lifecycle to call dragStarted when shouldDragStart returns YES. Cleanup of examples.