Update unread working, 40% done, next is removal

Got to the point where a user's account is being update with the number
of unread messages received while they were away. A notification appears
in their status bar, and they can then click the user block to remove
the unread count & read the messages.

The next step is to use this as a trigger to reset the unread count, and
also to work out a way to highlight the unread messages in the client
side.

Almost there ;)