New "Icon preview" module.

When you hover over the logo with "visual theme" enabled it spins. A very small change, but it's fun and represents what HN Special is all about.

Okay so it's lame, but I'm new to Git and am testing the waters. I hope to contribute actual solid features to this repo in the near future.

**Update: Added an "Icon preview" module. Please see [my comment](https://github.com/gabrielecirulli/hn-special/pull/54#issuecomment-39040090) about it.**