Referrer Policy issues + Chrome implementation status

As Daniel suggested on the call today, I labeled the open Referrer Policy
issues that I think are blocking PR:
https://github.com/w3c/webappsec-referrer-policy/labels/blocks-pr

The meat of it is: HTML integration for the 'referrerpolicy' attribute,
HTML+Fetch integration for the new policies, defining the CSS stylesheet
integration, and updating the web-platform-tests.

Also I wanted to give a quick update on the implementation work in Chrome.
A couple weeks ago we implemented the Referrer-Policy header as an
experimental web platform feature. If all goes well I'm hoping to ship it
for real sometime this quarter. Other implementation work upcoming is the
'referrerpolicy' attribute for <link> elements (https://crbug.com/595099)
and the new same-origin, strict-origin, strict-origin-when-cross-origin
policies (https://crbug.com/627968).

Thanks,
Emily