Add Loops and Screen Schedules to the selectable box in the Button Block

[rsalsbery]

This enhancement request is to make it easier for customers to set up Buttons on a Screen to start a Loop or Screen Schedule. Currently, if they wanted to do this they would need to View a Loop or Screen Schedule in their browser, grab the URL, and add it to the button Block via the URL method. This Enhancement will make it so they can select the Loop or Screen Schedule straight from the Screens list instead.

[Dan-Peck]

Merged in @ b44f130 and added to the queue for upcoming release to the live site.