REF: output z as int instead of float
REF: output z as int instead of float

Former-commit-id: e999e32700c0aa8bb3de3d6773c8a2ff2facf7b6
Former-commit-id: d518acfee79b05ea2c8ca93ff3934def53d13795
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox