OPT: now downloading data only once
OPT: now downloading data only once

Former-commit-id: 4a4d1ad3f002130f485174f25f93878b5194bcad
Former-commit-id: 57cc69d0c9f3c73c03de18b3491acf348c9cda18
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox