Add rel="noreferrer" to links when openLinksInNewWindow is on. Also add noopener when openLinksInNewWindow is on.
target="_blank" without also adding rel="noopener noreferrer" creates a vulnerability
(since the site you're linking to has access to the window.opener by default.
This adds rel="noopener noreferrer" to links generated by the makeHtml converter when openLinksInNewWindow is true.
Closes#670