Process sass in scss

There have been several requests to process sass comments in scss files. I think it's a good choice, but we cannot stop processing css comments in sass. This PR first tries to find css doc blocks and if that fails it will then try to find sass doc blocks when processing .scss files.

This isn't the cleanest way to do this but for now I'm trying to ease back into hologram maintenance and I think it'll be okay for a while.