DOC: check if user is sudo (if so, inform and exit program)
DOC: check if user is sudo (if so, inform and exit program)

Former-commit-id: da22db5f0fea6304709a7d0036c8cee4d33df1fc
Former-commit-id: 787adfe7001e9c8e5fea6f7a7cb57c88dfcbb434
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox