add basic gesture stuff

sorry, i have no idea what i'm doing...

![b7e](https://f.cloud.github.com/assets/48745/1212398/c26008ee-2617-11e3-8507-97a354346d7a.jpg)

i needed some gesture stuff for my [computering gem](https://github.com/phoet/computering) and hacked this together.

i would love to get some help with this