This allows you to add slides dynamically, even when moving backward.
To add a slide that occurs right before the current first slide write
code like the following:

var mySwipe = new Swipe(document.getElementById('slider'), {})
$('.swipe-wrap').prepend('<div>New Slide</div>');
mySwipe.setup({startSlide: 1});

This fork can be installed via bower with: bower install "swipe-js=https://github.com/axelson/swipe.git#2.2.4"