OPT: added useful module "is3d"
OPT: added useful module "is3d"

Former-commit-id: db5325bd8d632690cea1a16bc8f3931bdf430726 [formerly f0840dbe98fa06d0390f14b8c00f718f2a1dea6d]
Former-commit-id: c7505af50a7679874c98a4ec8cd58848fb6cbd7c
Former-commit-id: c3759de4f2b6604e3e9a4fb70497bf1dbeac5ac2
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox