REF: updated extract_centerline using module from smooth_centerline
REF: updated extract_centerline using module from smooth_centerline

Former-commit-id: 13cb18c8f3c3582efad88b5020cdfcaa624b6981 [formerly 4df865a1ce54bee9ced3f6ee6162b8f631177e76]
Former-commit-id: 0d31757797dadd59e196f8ef2075ef8fc67ce77d
Former-commit-id: 4e3d467e4ecb17ba1dab51f4322352d5707027c0
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox