This is related to #94 as it's also about comments appearing in the compiled css. I find it strange that when you request a sourcemap that the code forces comments on. Is that necessary?

The lines in question: https://github.com/dahlia/libsass-python/blob/python/sass.py#?L540-L541

The lines were added in fea52df but I can't really figure out why. @dahlia, is it okay to remove that?