NEW: in sct_maths: - allow multiple inputs/outputs (with check of matching numbers of ins and outs when necessary) - new options (-add,  -sub, -scale : intensity rescaling, can be applied as preprocess of another operation)
NEW: in sct_maths:
- allow multiple inputs/outputs (with check of matching numbers of ins and outs when necessary)
- new options (-add,  -sub, -scale : intensity rescaling, can be applied as preprocess of another operation)

3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox