BUG: the normalization of the intensity is now done by multiplying each slice by the normalization of the intensity along the centerline. The old code did not take into account slices for which the centerline presented no non-zero point. One mistake corrected.
BUG: the normalization of the intensity is now done by multiplying each slice by the normalization of the intensity along the centerline. The old code did not take into account slices for which the centerline presented no non-zero point. One mistake corrected.

Former-commit-id: 4998d95708e7a9292b9f382d008115629889b87e [formerly 1e8477a5fd13828c1d3d7d26d49e112f74294779]
Former-commit-id: 517a96686e43680740176c413035670a9e4fcf94
Former-commit-id: c000354413dddde5d19211db8c549f1771c23baa
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox