Initial Sass thing

Hey look, Sass.
Feel free to reject and close, this was just a fun Sunday project while watching a movie.

Turned all the colors into variables (although variable names could use some work).
Also killed all the vendor prefixes and tweaked autoprefixer settings. End result may be fewer actual vendor prefixes, but it all depends on what versions of browsers we want to support and how far back -moz- prefixes are actually needed.

Tried not to go too crazy with nested styles since you can get quickly lost with deep nesting and "&" references.

Ultimately may be nice to move the variable declarations out to include files, as well as maybe animations or other things. Since I removed vendor prefixes (per autoprefixer task), it negated the need for any mixins. Bonus!

Enjoy!