Refresh site Examples section

I feel honored to have one of my early CoffeeScript projects listed on the homepage, but nack isn't the shining example of .coffee source it was back in the early days. I feel like its wasting that spot.

If I may, I'd like to nominate another project, [The Atom editor](https://github.com/atom/atom). Its an enormous project written in CoffeeScript and I'd say is a phenomenal .coffee authoring tool itself because of that bias.

/cc @jashkenas @michaelficarra