Keep all messages.

Hi, 

I'm opening this pullreq so I don't forget about this branch and we'd have a place to discuss it. These patches have the desired effect as far as I tested it. 

The only thing I'm not sure on: would is be better to return from synchronizeMailbox(...) right away when remoteStart >= remoteEnd, or just have it finish up like I do now? ( I needs all the closing code anyway ).

Let me know what to change.
Thx