Enable input file with label at a specific disc (#1698)
Enable input file with label at a specific disc (#1698)

* REF: expose fname_label in main function

* ENH: introduced flag -initlabel (fixes issue #1697)

* REF: cleaning

* BUG: Adjusted label value due to old definition of disc label value

* BUG: fixed typo in input param


Former-commit-id: 170849bf0054f0ba51d5a418c3553867d000b396
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox