Changing svg logos to pngs

This should fix #133 once and for all. Svgs are a great idea, but we can't have nice things because WebKit…
![screen shot 2014-09-07 at 11 11 12 am](https://cloud.githubusercontent.com/assets/220240/4179172/66af3dee-36ba-11e4-99b8-3be0d4e154c2.png)

cc @rickcarlino @richleland @simonv3