Drag and Drop v1.5b

My first beta release of this. . . I've now added the ability to restrict what can be dropped where through a List of String called "Categories." This data input MUST be set on any DropZone, even if it is just an empty list. This uses an Object Variable named Categories of type List of String on the dragged object. 

*This will match if both the DropZone and Draggable have at least one matching item in their Categories lists.

This was a bit of a complicated addition so it's possible I've missed something somewhere that will break it or there will be edge cases where this doesn't work correctly. Please let me know if you find anything wrong so I can work on correcting it.