#504 SMTP: implement RFC1830 chunked transfer

[Sam Schinke]

If you use exchange and have problems receiving
email from hotmail or certain clients, try the
workaround in the link below until this is implemented.

This feature is discussed here:
https://sourceforge.net/forum/message.php?
msg_id=2027632

Implementation will have to wait until 0.19.1

Regards,
Sam