Instead of a multi-step process to display an unread message (ie. get
the original, notice it's unread, then update it, replace the message
with update one etc.), we now handle that in the (view /./..) command on
the server side.
Simplifies things, and is faster (which could be noticeable, esp. if
e.g. signature verification is part of the process)
3dc4b93989