OPT: msct_parser: add slash at the end of output_folder
OPT: msct_parser: add slash at the end of output_folder

Former-commit-id: fd480a9a6dfa041315de529179d9a4b53bcf16c2 [formerly 17946948fb36bb9b902b426fb2796433c7606cff]
Former-commit-id: 62fead68d24031154d1db6b2a666b352d844f03d
Former-commit-id: 3626b8176ac99a1e061e31b482106de7a62f0270
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox