List-Unsubscribe

[mindplay-dk]

Add explicit support for the List-Unsubscribe header, per RFC2369, e.g. in Message:

public function setUnsubscribeURL($url)
public function setUnsubscribeMailbox($mailbox)

Should add a header like:

 List-Unsubscribe: <http://www.host.com/list.cgi?cmd=unsub&lst=list>,
     <mailto:list-request@host.com?subject=unsubscribe>

Add documentation, perhaps link to here.

[mindplay-dk]

Pushing this to a future release, so we can release 1.0 ASAP.