Initial support for supplying kernel logos in kernel spec

![screenshot from 2014-09-24 11 58 38](https://cloud.githubusercontent.com/assets/327925/4393978/dddf862a-441c-11e4-8475-339c32e0a5f6.png)

Commence UI debate ;-)
I think it does (imho) I'm just wondering if it will show a 'broken image link' if there is no logo file. So you probably want a img.onerror.hide() maybe possible with css.