OPT: sct_asman: Affine coregistration for the first step, need to be improved
OPT: sct_asman: Affine coregistration for the first step, need to be improved

Former-commit-id: da4d57eec4c0aa58f45014ca6d5f151e79223222
Former-commit-id: 713f9987666b9580072fd5a65a5231bd4ac93e78
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox