Navigation Allows Navigation To Invalid Pages
The class disabled only affects the styling of the buttons: the buttons continue to function. I added the following lines to the end of the updateButtonBar function to add the disabled attribute:
<code>
(page == 1) ? btn_prev.attr('disabled', 'disabled'): btn_prev.removeAttr('disabled');
(page == total_pages) ? btn_next.attr('disabled', 'disabled'): btn_next.removeAttr('disabled');
</code>

This makes sure I can't navigate off the end of the icon selection pages (pageNum <= 0 || pageNum > numPages)
