libsass 0.4.0

• sassc has a new -w/--watch option.
• Expose source maps support:
  • sassc has a new -m/-g/--sourcemap option.
  • SassMiddleware now also creates source map files with filenames followed by .map suffix.
  • Manifest.build_one() method has a new source_map option. This option builds also a source map file with the filename followed by .map suffix.
  • sass.compile() has a new optional parameter source_comments. It can be one of sass.SOURCE_COMMENTS keys. It also has a new parameter source_map_filename which is required only when source_comments='map'.
• Fixed Python 3 incompatibility of sassc program.
• Fixed a bug that multiple include_paths doesn't work on Windows.