Feature: Add Author Links

Right now the links don't go anywhere:

![image](https://cloud.githubusercontent.com/assets/422899/4887104/efe8f570-6381-11e4-922d-7101cb2e710f.png)

In the future maybe we'll show a list of their posts, but for now we need to link somewhere so the reader can learn more about the author. I'll add a `link` attribute int he `_data/team.yaml` and include links that:

1. Go to github for devs
2. Got to dribbble for engineers
3. Got twitter accounts or about pages for other folks