nex3/sass — pull request #568 by crdev (2012-11-12 13:18:20+00:00)
Title: Correctly compute relative_sourcemap_path and pass it as String

0bea4d6b ("Add sourceMappingURL annotations to the sourcemap tests.") broke the sourcemap interchange:
- It was passed as `Pathname` rather than `String` expected by `Engine.render_with_sourcemap`
- `Pathname.relative_path_from()` expects a directory as an argument but received plain sourcemap filename instead