Load Spinner as modal

[felipe-canaviri]

Hi there,
I really like iOS-Overlay and I already integrated it to my project and works like a charm. Nevertheless, since the spinner is displayed when a form is submitted, it would be great if the spinner can be loaded as a modal so all the other UI controls can be locked. Also, this could be configurable in the 'opts' variable.

Thanks so much for this great tool !