Add support for Sass and SCSS.
Fixes for Sass/SCSS converters.
Allow users to specify options for Sass.
Consolidate into one master 'Sass' converter.
Build Sass configuration options.
Don't allow path traversal or syntax overrides.
Does not allow caching.

This was done to prevent putting the .sass-cache folder in bad places. Needed? cc @benbalter.
Make sass a runtime dependency.
Add docs for Sass conversion.