New keywords for RESTART MODE in 3D (as in 2D)
As done for RESTART MODE in 2D recently introduced for v8p4 (#727), 2 new keywords can be introduced:
- RESTART FILE PRINTOUT PERIOD (possible use to secure periodic savings of very long computations in case of crash),
- RECORD NUMBER IN RESTART FILE (possible use in data assimilation, when the last observation is not the last time step).