This adds the required bits to wayland surfaces and ties them up
to the compositor parts.

The central part here is to recalculate the surface size accordingly
and to translate surface damage into buffer damage.

The choosen approach additionally lays groundwork for wp_viewporter
support, which is closely related in its nature.

A further explanation of buffer transforms from the specification:
> The purpose of this request is to allow clients to render content
> according to the output transform, thus permitting the compositor
> to use certain optimizations even if the display is rotated.
> Using hardware overlays and scanning out a client buffer for
> fullscreen surfaces are examples of such optimizations.