OPT: sct_asman: changed the first co-registration step using ANTs
OPT: sct_asman: changed the first co-registration step using ANTs

Former-commit-id: 73bc314835d1e06d730a41b40d2dde04def6c965
Former-commit-id: 367f6e7d5660deab79eafb918ec39694d7a095df
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox