Feat: add styleguide

* This branch adds the styleguide [note: still a WIP as far as the CSS for the styleguide itself].
* Also refactors much of the existing code to fit within the context of the styleguide (break markup & styles into smaller partials).
* General cleanup (removing unused images, empty files, etc.)
* Significant improvements to the README

Fixes https://github.com/sparkbox/sparkbox-website/issues/5

![screen shot 2013-11-09 at 10 39 09 pm](https://f.cloud.github.com/assets/1767309/1507895/b26afac8-49b9-11e3-9821-998cf0e8fc67.png)