Creates a new Scatter instance.
Target can be either:
Options is an object, see Options page.
Change Options after an instance has been created.
Arranges items into their chosen positions based on Mode.
Selects the specified item - moves to center, increases z-index, and applies scaling and class as per options.
Index is one of three things:
When an existing item is selected, discard is called automatically.
De-selects the specified item, returns to original position and removes class.
Selects the previous item.
If called when first item selected, loops around to last item.
Selects the next item
If called when last item selected, loops around to first item.