Consider frontpage with highlights

The current page with categories can be replaced with something better. Maybe something like the Concerto frontpage?

I think the idea might be that we could mark a category with a featured flag that would display it on the home page where the root directory is currently listed. I don't know if we would want to hide the root category listing, or just bump it down below the "Featured Categories" section.

I'm taking a look at the code right now, and I'm debating whether to modify the categories controller to do this (looks messy) or creating a new homepage controller to take care of this.