Avoiding the demo server to crash on 404

While trying the demo, I encountered a problem: the server always crashed.
It appears the browser was request a `favicon.ico` file, thus using the *else image/png* route and ending as an exception as it is sync read by node.

Also, I added a `package.json` file as a convenience to use `npm start`.

![](http://i.imgur.com/i4dngEY.gif)