DDMsgReader: Fix for #499 (replying to emails from unknown user)
DDMsgReader: Fix for #499 (closed) (replying to emails from unknown user). Also, DDMsgReader no longer changes the 'from' name in a message header to "All" if it's blank. And now there's also no need to check for "All" when replying to a message (only check for an empty 'from')