Slide-like cover + all curriculum resources layout beta

This improves on the effort of https://github.com/github/training-kit/pull/164 and implements a slide-like cover for each section, filling the screen and making presenting/screen-share webinar walkthroughs cleaner.

All resources and information remain, but are simply "below the fold" of the TOC link sections.

![1](https://cloud.githubusercontent.com/assets/352082/4062434/c06f9374-2dff-11e4-861b-de4e03bd55bc.png)
![2](https://cloud.githubusercontent.com/assets/352082/4062433/c06ddd40-2dff-11e4-8343-0acca56b853f.png)
![3](https://cloud.githubusercontent.com/assets/352082/4062435/c070abb0-2dff-11e4-9110-5bf1e64c6fba.png)