Add tessel example program and add node.js cruft to gitignore

@jonathanstark Take a look at this (pardon the giant image)!
![screenshot_2014-10-02-20-36-12](https://cloud.githubusercontent.com/assets/2587335/4501602/2f382d80-4ab0-11e4-8a32-77f9994b938d.png)