NEW: new extraction method: thresholded weighted-average
NEW: new extraction method: thresholded weighted-average

Former-commit-id: 7acf813bdbcaf024a2b9c548c60008df7dfb9e8d [formerly 7a09a7bca3e9a93d2b9cedfa9c93686c0874089e]
Former-commit-id: 882937e258ab1be9a30a548af4a0b8de9aab77aa
Former-commit-id: 7b9fc18593754df9f8aaa4fcf3560694fcb0920b
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox