plasma: QGraphicsView-ectomy

[Marco Martin]

Hi all,
I've committed in the kdelibs branch plasma/mart/qgvremoval a pretty big diff.
it makes Applet inherit only from QObject this causes a nice doino effect:
all api that was coming from QGraphics* isn't there anymore, so i had
to cut pretty badly, and that's good, because i think the applet class
can become signinficantly smaller.
at the moment the built library is about a megabyte less than the 4.9
version, i hope we can go down at least another one ;)

some things are still disabled:
* toolboxes: should be simple qml components, the containment just
exposes the list of actions
* popupapplet: will probably need a different implementation, and not
be different from applet (all applets are popupapplets if they expose
the right components or sth like that)
* view: will probably have to live in a specialized library
* tooltipmanager: still dependencies to remove, then may return in libplasma

other things may go shortly, such as applethandles

this should *really* need a deep review, so any help is appreciated :D

Cheers,
Marco Martin