libplasma GPL files

[Davide Bettio]

Hi,

I think that we should change the license of the list below of files from GPL 
to LGPL:

* dialog.cpp
* dialog.h
* extender.cpp
* extender.h
* extenderitem.cpp
* extenderitem.h
* tooltipmanager.h
* tooltipmanager.cpp
* popupapplet.cpp
* popupapplet.h
* private/extender_p.h

Bye,
Davide Bettio.