Update to node-sass 0.9.2 for #26

This pull request updates the dependencies to node-sass 0.9.2 to address the bug reported in #26

Because of a known issue in node-sass 0.9.2, source maps won't work.
https://github.com/sass/node-sass/issues/337

So this pull request has the default settings for `sourceComments` changed to 'none'