apply new session logo

![screen shot 2014-12-05 at 12 58 48 am](https://cloud.githubusercontent.com/assets/459648/5303224/ff3553e2-7c19-11e4-8c20-b9eebbf559d2.png)

incorporate https://github.com/sfphp/Station/pull/44#issuecomment-65667827