Replace direwolf icon

[xssfox]

I commissioned Kat from http://cmykatgraphics.ca to redesign the logo based on the existing logo. 4 different styles are provided. The source contains SVG versions which can be useful for higher resolutions.

The images are unique (not used anywhere else) and copyright / intellectual rights remains with direwolf project.

Fixes #447

[darksidelemm]

This would be really cool to see included!

[darksidelemm]

Bumping this, it would be great to see this icon used!