break interface.

Implement special CreateDevice behaviour

Signed-off-by: Axel Davy <axel.davy@ens.fr>
Change behaviour on missing buffer sharing functionnality

Signed-off-by: Axel Davy <axel.davy@ens.fr>
check PIPE_CAP_CLIP_HALFZ

Signed-off-by: Axel Davy <axel.davy@ens.fr>
Use VS_WINDOW_SPACE when implemented

Signed-off-by: Axel Davy <axel.davy@ens.fr>