REF: simpler name for the warped grid (qc for register_graymatter)
REF: simpler name for the warped grid (qc for register_graymatter)

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