I have added two new template funcs, absURL and relURL.
They are documented here https://github.com/spf13/hugo/blob/master/docs/content/templates/functions.md
When Hugo 0.14 is out in the open, I would say that these should be the recommended way to link in static resources like CSS, JS etc. It’s much easier to handle missing or too many trailing slashes etc. in a Go func, compared to a template.