Support start slide on setup

[axelson]

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('

New Slide

'); 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"

Fixes #28

If you'd like I could add some docs as well.

[axelson]

Any thoughts on this? Would be nice to support reinitializing (better performance then a complete kill and new instance I think) for dynamic content.

[axelson]

Any chance on getting this merged? I can fix the conflicts if so.