Social icons, and three ways to handle the footer

New

• Add your social links under Settings and they appear as icons in the email footer.
• Choose the built-in footer, write your own, or turn it off. The unsubscribe link stays locked into the built-in footers, and a one-click unsubscribe header is always sent.

Fixed

• The unsubscribe link in a test email hit a 404. It now opens a clear test page and never unsubscribes a real contact.