removeChannelTab made the Server tab active whenever it closed a
channel's tab. When a part or kick came from another client, the user
lost the channel they were reading.
It now finds the tab the user was reading by its name among the
remaining tabs and keeps it active. Only when that was the closed tab
does the Server tab show.
When the kicked nick is the user's own, the kick line also goes into
the Server tab, which counts it as unread. That copy carries the
event's id with "-server" added, since addMessage drops an id it has
already seen.
Model: opus-5-5
sneak