New --root option not supported when building styles

[fdanielsen]

The new --root option is very handy, in particular when you want to use shins as a standalone builder without the source files directly in the repo. We've created a Docker image that contains the shins source, but mount a separate volume as root which then contains the source and pub directories, which are then the only things in our repo.

But we currently can't use the buildstyles.js script, since it doesn't care about --root at all.

Also to mention, it would really be nice if the --root option changed the output location of index.html automatically rather than have to specify that through --output, since all references to resources in the generated HTML is relative to root.

[MikeRalphson]

Fixed in shins@2.3.2-5.