Created by: veracarr
I added an additional function itemPostRender to allow developers to customize particular dropdown results. By default, this just returns the HTML that was originally rendered. In the screenshots, I show some examples of how I leveraged this functionality to add a dividing line and loading indicator.
I additionally added logic into render to check that the items list is not empty. This is a safeguard, to handle the case where a user potentially returns null for all items' HTML.
