Double-click for expanding collection root item

[Mark Kretschmann]

Heya,

the double-clicking for expanding the collection root item is
unacceptable. I don't know how this code was sneaked in and how it
managed to pass our usability team, but it's obviously a no-go.

First of all we cannot rely on double-clicking anywhere without
providing an alternative (which we normally do in such cases), and
secondly this doesn't even obey the global KDE system settings (mine
is set to single-click). Last not least this can become a complete
deal breaker for new users, who cannot figure out how to open their
collection.

I'm really a bit puzzled about this commit. We should definitely fix
it before tagging - a single-click would e.g. work fine.

-- 
Mark Kretschmann
Amarok Developer
www.kde.org - amarok.kde.org