DEV: beauty improvements on straightening optimization pipeline
DEV: beauty improvements on straightening optimization pipeline

Former-commit-id: c0ab37aada2a9a268d915921ae17e0992a914ae6
Former-commit-id: 13996c1797772c0ba62992f44f1260f47017e757
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox