#148 Don't count nickchange as activity

[Klaus]

I have all channels logged in one file.
When someone changes nick, it is counted as activity
for alle channels. So if someone changes nick at 4.am it
is shown on the stat for alle channels.

So it would be nice with an option to disable nickactivity
on "thirdline".

I could disable thirdline in my own format module, but I
want the NickTracking to work.

At this time I commented out stat in LogParse.pm, but
that would be overwritten on the next version ;-)