Some SMTP tests made use of disabled addresses. We stored addresses
in a map, meaning the order was randomized. This lead to tests sometimes
attempting to authenticate over SMTP using a disabled address, failing.
Add special case handling for draft messages so that if a Draft is
updated via an event it is correctly updated on the IMAP client via a
the new `imap.MessageUpdated event`.
This patch also updates Gluon to the latest version.