Remove the geometry from the wayland surface

Remove the geometry from the wayland surface

and add pos and size properties instead. The pos is a PointF while the
size is a integer based Size since pos can be transformed, while the
size reffers to the pixel size.

Change-Id: I5d84aa6661405cb0df356b787246d0d73ad0c503
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>