Show screen name based on output model

Platform screen now returns the screen name.

Change-Id: I190da6b4d89774dd25de8353615fe7dcaeb11cd4
Reviewed-by: Jan Arne Petersen <jan.petersen@kdab.com>
Reviewed-by: Andy Nichols <andy.nichols@digia.com>
Implement QPlatformWindow::raise() in QWaylandWindow and relay it to the compositor

Change-Id: I744f9799730810e4afc73f86487a34aa0fd8405b
Done-with: Vesa Halttunen <vesa.halttunen@jollamobile.com>
Reviewed-by: Jan Arne Petersen <jan.petersen@kdab.com>
Reviewed-by: Andrew Knight <andrew.knight@digia.com>
Reviewed-by: Andy Nichols <andy.nichols@digia.com>