NEW: option to compute cha without curvature correction
NEW: option to compute cha without curvature correction

Former-commit-id: 7ee501daf2dc9c5189bad65a2c43126e0e630d62
Former-commit-id: 2136fa6195ead164909c2ddc915e144d84bf9ea9
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox