Update home page layout.

Closes #687 

![home-page-responsive2](https://cloud.githubusercontent.com/assets/96776/3901905/6c21af42-22b4-11e4-9c40-bd12333fcc82.gif)

### Breakpoints

#### Large
![large](https://cloud.githubusercontent.com/assets/96776/3901908/8addb9da-22b4-11e4-86f0-559858384f72.png)

#### Medium
![medium](https://cloud.githubusercontent.com/assets/96776/3901912/907aa128-22b4-11e4-87ac-14dd56633f3b.png)

#### Small
![small](https://cloud.githubusercontent.com/assets/96776/3901914/96e96bb6-22b4-11e4-869f-754a8167d95f.png)

#### Extra small
![extra-small](https://cloud.githubusercontent.com/assets/96776/3901915/9c80e1c6-22b4-11e4-98ef-c2ad3e33e219.png)