Group licenses together

Proposed fix for #29. This groups licenses into "families". The main link links to the most used or latest version of a license.

Note that as part of this change, I shortened the license names in the list...

![license-list](https://f.cloud.github.com/assets/19977/1424835/21b2de2e-4027-11e3-93d2-dd3a6b13c337.png)

...but kept the full name in the license detail page.

![license](https://f.cloud.github.com/assets/19977/1424834/1f9eeea2-4027-11e3-884b-5f47b4f7affc.png)

Would love to get some feedback on this approach: /cc @benbalter, @aden, anyone else?

Also, @jasonlong, I wonder if there's a better way we could present the licenses that belong to a family? Listing them inline in the text could do for now, but if you have ideas to present it better, I'd love to hear them!