Responsive and Beta fixes 

Based on early feedback:
* Fixing the column sizes at the medium browser size,
* Adding beta to the logo and mention this on the about page.
* Optimizing header landing-page section for mobile.
![screen shot 2014-08-05 at 11 21 46 am](https://cloud.githubusercontent.com/assets/1807325/3813553/40a4f744-1cb4-11e4-8e2d-762b02b2df80.png)