OPT: register_to_template: smooth centerline before registration (issue #610)-- NOT COMPLETE (use fslmaths)
OPT: register_to_template: smooth centerline before registration (issue #610)-- NOT COMPLETE (use fslmaths)

Former-commit-id: 662355c76c232d247f86bc782b91c785aac19a26
Former-commit-id: 3166dbbea627fc10cab704379257e230f79989a5
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox