OPT: create tmp dir and load manual GM segmentation (as list)
OPT: create tmp dir and load manual GM segmentation (as list)

Former-commit-id: 2e3bfc0bf1bcfd34e318e40e0f4f5fae698e2fa9 [formerly fab4e743591596419dbac6a0b808c36751a743d9]
Former-commit-id: ce6ea67c7ae7844bd0691893da83b0640a5f7237
Former-commit-id: c408629ef7affbbdb3ae55ce2729665d61ef61fa
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox