Support SASS

[G0dwin]

This is a large task and I don't intend on taking it on anytime soon, however it would be a really nice feature to display coverage for the original SASS (or scss) files instead of the compiled versions. SASS that is compiled as verbose contains comments that show which file and which line the SASS was compiled from so it should be feasible to load the original file and display coverage there instead.

I would recommend this to be it's own project marmara-sass so that non-sass users can avoid picking up unused dependencies.