#158 - Fixed layout of AboutViewController

Issue: https://github.com/wordpress-mobile/WordPress-iOS/issues/158

Moved contents to a scrollview:

![ios simulator screen shot nov 18 2013 9 19 41 am](https://f.cloud.github.com/assets/3904502/1564884/b6646b1a-5075-11e3-8e3d-75a6187f6c1d.png)
![ios simulator screen shot nov 18 2013 9 19 43 am](https://f.cloud.github.com/assets/3904502/1564885/b6d39f1c-5075-11e3-8c45-47973c8673cf.png)