Change redirected HTTP→HTTPS links to HTTPS.

Also changed one other domain-level redirect to the canonical URL.
Fix invalid protocol-relative links to http://.

If the site were being served across any protocol other than HTTP (i.e.
HTTPS), these links would have been broken.

All of these had either no or an invalid SSL certificate, with the
exception of All Things Luxury, which despite having a valid SSL
certificate has a site that is partially broken in some browsers due to
mixed-mode content, which some block by default; for that reason, I
guaranteed its link to be HTTP rather than HTTPS.
Fix broken image references in minting page.
Fix redirected/bad protocol-relative links.
Fix a bunch of typos and tiny HTML errors.