Add Pinch-to-Zoom Support for Mobile

[leoherzog]

Phones unsurprisingly choke when loading the site, but tablets are able to render it pretty well. It would be nice to have zoom gestures for Android and iOS.

[thkruz]

You could add a few extra lines of code where the scroll to zoom detection is. Good reference: http://stackoverflow.com/questions/11183174/simplest-way-to-detect-a-pinch