Make a degraded icon for mobile, even on App Market

[orblivion]

Coming out of #42

It would be nice to be able to have a less detailed version of the icon when it has to be really small. Particularly on mobile, even when looking at the App Market. People tell me it's too detailed, they can't see what's going on in the picture. Even 128x128, when used on desktop, I think it's okay as-is and I'd hate to degrade that image.

I think this would require changing the Sandstorm App Market. I think it uses the same image on the mobile version.