kgtk by default

[Harald Sitter]

https://bugs.edge.launchpad.net/ubuntu/+source/kubuntu-meta/+bug/281834

Last I checked kgtk was a really really nasty hack and didn't work all
that well (+ upstream states that it doesn't work with all GTK+ apps).
Unless someone wants to polish up kgtk or implement a more sensible
approach I would reject the wish and create a needs-packaging bug so
that those user that want to use it can obtain a package easily.