OPT: crop the image around warping field space at the end of sct_apply_transfo
OPT: crop the image around warping field space at the end of sct_apply_transfo

Former-commit-id: dd03413a2709e999844dc50d12cbefc080e04d67
Former-commit-id: 2ab9dc12d0795b4594ee0a2bd4bdffcf6b58ab1f
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox