halfway done port of the KDE3 menuapplet

It compiles and starts, but doesn't find topmenu windows.
The support in KMenuBar for this seems ported, but somehow ( info.windowType(SUPPORTED_WINDOW_TYPES) != NET::TopMenu ) is always true in the plasmoid.

Needs investigation. Best by someone who has more knowledge. Lubos? :)

Geometry stuff is not done, too, as Plasma is currently a moving target.