OPT: Better visualization of the dictionary and/or target coordinates in the PCA space
OPT: Better visualization of the dictionary and/or target coordinates in the PCA space

Former-commit-id: 6c92493c99d77db07780ea9531c360b51134c4d6
Former-commit-id: 15759d97e4bf3b6cb4a8150f3856eb038dac663d
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox