The KoShape::shapeChanged virtual hook has always been called when
one of the properties of a shape changed; I expanded that by making
it also get called when another shape is changed in the bounding rect
of the shape to allow a shape to update itself if thats needed.
Note that I added a collisionDetection() boolean so there is little
impact on performance for those that don't want it.

This effectively finishes the runAround of KWord to make sure layouting
is changed when a shape is moved above it.

svn path=/trunk/koffice/; revision=619584