chore(build): Adding Sass to Grunt pipeline

Adding Sass and Autoprefixer into the mix. This also means we need a dist/ directory, so things are about to get "weird".

Took a rough stab at documenting the available Grunt tasks, although some are subject to change once we get minification and other things involved.
Awesome. I was also looking into https://github.com/JohnAlbin/normalize-scss which seems to be a Sass port of normalize.css. Not sure if it'd be a "win" or not.