Scrollview with draggable item adding

This library adds a new type of scrollview widget to the widget.* library under the name widget.newDragItemsScrollView(). The scroll view can then have display objects added to it which can be dragged off the scrollview by either touching and holding or pulling them in a given direction. All of these features can be configured per item being added to the scrollview, including turned off. The dragging-off of the items needs to be handled by a listener which can be copied from the demo main.lua. The idea is that the parent code takes the focus of the item being dragged and handles whether or not the item should be removed from the scrollview or a duplicate created.