Set max-width on homepage blurb

Before:

![screen shot 2014-08-17 at 10 29 55 pm](https://cloud.githubusercontent.com/assets/688886/3946929/aae94fd6-267f-11e4-8d60-b206997ff03c.png)

After:

![screen shot 2014-08-17 at 10 30 18 pm](https://cloud.githubusercontent.com/assets/688886/3946932/b4314e0e-267f-11e4-84d3-59bb1742ce85.png)