* Fix all stylelint errors
For any errors that fixing would require changing the output of the css disable stylelint for that line instead of modifying.
* Update quality.py
Make stylelint quality check pass when there are no errors
* Delete empty selectors
Two endpoints are intended to be used by AJAX calls from the web UI with an
authenticated user. When enabled, the value of the preference is an encryption
of the username, to be used as a token for one-click unsubscribe links. The
third endpoint is the target of unsubscribe links, which displays a page with
an appropriate message to the user.
