Let the viewer tile options be multi select

[idugan100]

We want the below menu to be multi select. For example, we want the user to be able to choose to see kitty hawk and eastern Maryland tiles at the same time.

[Thejohnmeyers]

As of today, we have a loop that is getting all of the tiles selected in the java script but we are trying to use the urls function from open layers but it is struggling to load the correct tiles doing some more research as of now