title: Send Email from Firefox Extension
body: <p>What is the best way to send email from a Firefox extension?  I can't just execute a mailto: link, because I need an attachment (actually, I really need a specific MIME-encoding, so I'd like full control of my headers).</p>
  
  <p>Worst-case I can speak SMTP to the user's SMTP server I guess... is there a raw socket request ability in Firefox?</p>