INST: improved management of version.txt
INST: improved management of version.txt

Former-commit-id: 746f9d7b07951d6087f7a450e4e3e7bd884e86ac [formerly 682084556cd846ce1d2a2a46134b3f5b1c7f091a]
Former-commit-id: f0e2a261d626958c70d8bdcee9919b91f7c779a3
Former-commit-id: 277bf235247bafdf48c45b6844ac4941e808d399
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox