NEW: msct_image: if the image to crop if smaller than the square mask : image symmetric padding to fit the mask
NEW: msct_image: if the image to crop if smaller than the square mask : image symmetric padding to fit the mask

3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox