Support SCSS

[sindresorhus]

Now supported through a custom parser in autoprefixer@6.0.0:
https://github.com/postcss/postcss/#custom-syntaxes
https://github.com/postcss/postcss-scss

I don't have time to do this right now, but PR welcome :)

[gjjones]

Do you mind if this project takes on postcss-scss as a dep for the feature?

I guess it depends on whether you want this extra syntax to bring about a plugin style system or if it is alright to own capabilities for what sublime-autoprefixer can do.

[sindresorhus]

Sure. You can see how it was solved in sindresorhus/atom-autoprefixer@fc02483.