Enable to disable software rendering if the app wants to use it

Signed-off-by: Axel Davy <axel.davy@ens.fr>
Break interface to handle new Ex parameter

Signed-off-by: Axel Davy <axel.davy@ens.fr>
Implement ResetEx and fix Multihead Reset

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