OPT: adapt image origin given its orientation and the default orientation instead of the sign of its origin before padding
OPT: adapt image origin given its orientation and the default orientation instead of the sign of its origin before padding

Former-commit-id: 68b7cfb664d5132e8338208802f99132fb2768de [formerly 2e89843bf18b996a902da7f8cd1971d0f88fa1dd]
Former-commit-id: b7c38201ef99bab6a52bcbc22e134f8577c31188
Former-commit-id: db012429dbcec847cbb2915559c9243ed84c2d64
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox