When the settings "Hide Join/Part/Nick events" "Except for watched nicks active within the last day" are enabled, Join events are never shown, while the other two kinds of events are shown correctly for recently active users.

This is especially bad and misleading when someone is doing a quick reconnect: you only see them leave and think they are gone.

Reproducible: Always

Steps to Reproduce:
This requires an interaction of two IRC clients/users. They will be shown as [A] and [B].
[A]:
1. Join any IRC channel in Konversation
2. Go to Configure -> Behavior -> Chat Window
2.1. Check "Hide Join/Part/Nick events"
2.2. Check "Except for watched nicks active within the"
[B]:
3. Join the same IRC channel
4. Send any message
5. Leave the channel ([A] sees the Part notification)
6. Join the same IRC channel ([A] doesn't see the Join notification, which is the problem)



Actual Results:  
Join events are never shown when "Hide Join/Part/Nick events" is active. Only Part and Nick events are shown when "Except for watched nicks active within the" is active.

Expected Results:  
Join events for recently active nicknames should be shown with "Hide Join/Part/Nick events" "Except for watched nicks active within the..." active

This happens because all information about a nickname's last activity is deleted when it leaves. I tried to fix this but there doesn't seem to be a nice and simple solution. The objects that store this information really need to be deleted.