#570 Allow reply to complete after replied-to message deleted

[Dan Taylor]

If you reply to a message, then delete (or move) the original message before the reply has been sent, the reply fails, even though all parts of the message that should be necessary to send it appear to be in the reply. Behavior seems like it should be to allow the reply to complete even though the original message has been deleted or moved.

[Paul Lesniewski]

When replying to a message, that message needs to be marked as replied.

[Paul Lesniewski]

... and certain headers in the reply (In-Reply-To/References) are built using the original message