OPT: now get slices corresponding to vertebral levels based on the (fitted) centreline position
OPT: now get slices corresponding to vertebral levels based on the (fitted) centreline position

Former-commit-id: 3246889c75483e56726d7c05604f2096a66e3aa6 [formerly eb3efa16f12239e7366d0355f4c68a778ceea402]
Former-commit-id: 22de479235b83e646fd3105f5c0a3e061765b31e
Former-commit-id: 66f1176dfb52945b0a6ad34437111b5dd107baeb
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox