[Freeciv-Dev] (PR#12122) mapview sliding should be enabled by default

["Jason Short" <jdorje@xxxxxxxxxxxxxxxxxxxxx>]

<URL: http://bugs.freeciv.org/Ticket/Display.html?id=12122 >

Mapview sliding (the client option) should be enabled by default for
2.0.  Some time in the 300-500ms range would be okay.

There may be a few bugs we can fix here too.  When choosing next-city in
the citydlg there should be no sliding, for instance.  This should be
easy to fix.

Perhaps there should also be a minimum-speed of like 1000 pixels per
second.  So if you're sliding a small distance the full time will not be
used.

-jason