Fixes #7 by defining _repr_html_ and _ipython_display_

This fixes the rendering of the dictionary in IPython notebooks. You can read about the rendering systems [here](http://nbviewer.ipython.org/github/ipython/ipython/blob/2.x/examples/Notebook/Custom%20Display%20Logic.ipynb)

![screen shot 2014-12-13 at 20 47 08](https://cloud.githubusercontent.com/assets/4310904/5425331/1cd07e94-830a-11e4-9d3a-2a7b2430afae.png)