NEW: visualize warping field for quality control (flag -qc)
NEW: visualize warping field for quality control (flag -qc)

Former-commit-id: c00ad0f4d05b7e9e6324ee2f26d4e689fd78bbac [formerly 8405a2af0acede8506483d2c8a9af15ad81ec1b3]
Former-commit-id: 96efe2e4d1e670ec1329b095bcc79e9dd6e033ec
Former-commit-id: b1407ee3eee0100b01ad9930151daac7a58f73a4
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox