Investigate `sass-convert` embed

[pascalduez]

Convert sass-convert from Ruby to JS and embed it.
http://opalrb.org
Probably with a post-install script, fetching the lib from Sass repo.
This would prevent from running those pesky binary checks.

[valeriangalliat]

This software don't work for me, installed via gem, I get a uninitialized constant Opal::Tilt (NameError) trying to run opal test.rb (sample test file from their homepage).