Improve documentation?

[shelbyKiraM]

It is not immediately obvious what the sorting criteria is for sort-sass. Can you explain in the readme?

[miraks]

Sure. I'll explain it soon. Ordering is hardcoded right now, you can see it here https://github.com/miraks/sort-sass/blob/master/src/order.coffee. I think I'll add an option to change this.

[Grawl]

#3