Drag and Drop v1.2

I have now updated the subgraphs to accept a Boolean data input for enabling and disabling the functionality on the fly. There may be some unexpected functionality with this implementation though, so let me know if you see any problems. My testing so far has shown me that it seems to work the way I expect. 

I still have a lot more functionality I intend to add to these subgraphs to make them more useful but they will take some time to implement. In case you're interested in what I plan on doing, here's a taste. . . 

I'm going to add trigger outputs to the subgraphs for certain actions, like picking up and dropping an object, and I'm going to add a way to specify "categories" to control what can be dropped where.