OPT: added output option for sct_register_to_template
OPT: added output option for sct_register_to_template

Former-commit-id: 5d526829bbb42c13c0b6804bd304de67ea3bd0bb [formerly 1d225bac566908853bcebe67cdf4564d23c6d034]
Former-commit-id: 87f4bf83e74048525b17a2089efb6a95c3d5cb92
Former-commit-id: d56446127a759ff81edfb1e9fea568e4b485b394
neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox,neuropoly/spinalcordtoolbox