Switched to using TouchSwipe library; fixed scroll-to bug

Trying out the TouchSwipe plugin for handling swipe events: https://github.com/mattbryson/TouchSwipe-Jquery-Plugin. It seems to be more sophisticated than the plugin we've been using. It's currently configured to have a max time threshold of 1 second: any swipes with a longer duration will not activate the comic swiping function. It also only accepts swipes using 1 finger. This means that 2+ fingers can be used to scroll or pinch. We can play around with these settings to see what makes the most sense.

Also some of the recent code reorganization seems to have broken the scroll-to functionality. It only seemed to be working on the initial bookmarklet load. I think I've fixed that issue as well.