Add touch support for some mobile devices

Closes #4 (as far as I'm concerned)

Works on:
* Firefox 19 for Android (and probably other recentish versions)

Sort of works on:
* Chrome 18 for Android (doesn't disable double-tap zoom)

Does not work on:
* Android Browser (doesn't like websockets)

Not tested on:
* Mobile Safari
* Any of the Operas
Merge pull request #33 from pao/topic/mobile

Add touch support for some mobile devices