Fixed full_logo scaling problem in About activity.

The logo on the About screen was cropped on smaller screens. This should fix it.

<img src="https://cloud.githubusercontent.com/assets/3090888/2875916/c8452e36-d429-11e3-942a-874602e6d294.png" width="50%" /><img src="https://cloud.githubusercontent.com/assets/3090888/2875917/c8513f5a-d429-11e3-8064-7d63a3dbd244.png" width="50%">