This fixes the painting of shapes to appear in random order.

This also changes the way the painting of the shapes is done. Now the
shapes are painted by their hierarchy. This means it is no longer
possible to have shapes in different layers that are drawn mixed.
(Meaning shapes from on layer are drawn between shapes from a different
 layer.)
Also the reorder commands have changed to make sure the created
z-index's are allways unique in one level of the hierarchy.
The creation of the layers are fixed to create a unique z-index.
No command will be generated if the order has not changed, e.g. if the
top most shape is risen.
The feature to raise above a shape overlapping the risen one gone for
now. Not sure if it is possible with the used algorithm.

BUG: 185952

svn path=/trunk/koffice/; revision=1030297