Updated code to ensure a drop zone is active only when it and it's ancestors contain the touch point. This prevents the hidden parts of a UIScrollView child from being selected as the drop zone. Cleaned up code to make it more generic. It now works with a HyDragAndDropManagerDelegate so that the containing code has more control and does not necessary have to subclass UIViews. Refined the UIScrollView autoscrolling to prevent the scroller from jumping.