OPT: reduced sensibility of checking if two images are in the same space. Fixed #752
OPT: reduced sensibility of checking if two images are in the same space. Fixed #752

Former-commit-id: 746b678913028d992d1092eb9ad6eb7235e381ed
Former-commit-id: a2c7b43b7971ca2827e3abc0306b12d498b61574
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox