finished implementation of vert level — now need to add flag
finished implementation of vert level — now need to add flag


Former-commit-id: cede6079032f9930e498eb1a7f385a838bc8e1b0
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox