Badgetastic styles

This tracks the implementation of the [badgetastic](https://etherpad.mozilla.org/badges-styleguide) styles, along with some general cleanup and organization of the backpack's CSS files.

- [x] clean out old, crufty CSS files
- [x] install LESS middleware
- [x] get bootstrap [bootswatch skinning](https://github.com/thomaspark/bootswatch/tree/gh-pages/swatchmaker) equivalent set up
- [x] implement new styles

It's not done yet!

<!---
@huboard:{"order":254.0}
-->