Fixed centering on logo

Fixed the centering issue on the logo.

![apple-touch-icon-precomposed-1](https://f.cloud.github.com/assets/3453188/1101889/355cdd2e-17e8-11e3-929a-50e5c52e80cd.png)


![apple-touch-icon-precomposed](https://f.cloud.github.com/assets/3453188/1101887/1e00c3ca-17e8-11e3-88ae-ebee252e7197.png)