OPT: msct_register: added angle threshold for centermassrot
OPT: msct_register: added angle threshold for centermassrot

Former-commit-id: a513d2f22f07124e0468c2a08d67a331ce3a12be
Former-commit-id: ffebe1dd1989b18874fe0474bf35a4e23db6fe36
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox