OPT: added file_output option in parser
OPT: added file_output option in parser

Former-commit-id: d8d81106e0e17d52a3c60b01f9eb8f164fb88cbb [formerly 3008c515e806492729661e2d7d9fb0eb24efbfb4]
Former-commit-id: a24986a06cbe3455eab4bd148829f82ff6ed070d
Former-commit-id: 3a7ef51d6ca5a59debd73315e6e461a1cec55cdd
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox