License family tabs

@Haacked Here is a pull based on your branch for #111. It still needs some wiring up of things for the variation-specific rules tables. Right now, I've got it dummied up to render the GPL tabs for every license. Hopefully the pattern is clear enough that you can drop in the rest of the logic.

Also, note that I created a new partial for the license overview sections (featured vs. other) since that code was identical.

Obligatory screenshot:
![screen shot 2013-11-06 at 11 23 39 am](https://f.cloud.github.com/assets/6104/1483985/685ab89e-4700-11e3-9212-287043353aab.png)

Let me know if I can help with anything else on this.