NEW: script to plot absolute error as a function of noise std and tracts std
NEW: script to plot absolute error as a function of noise std and tracts std

Former-commit-id: 1d3a6833bf1bc4ad8ab5b7195d198dffd08c483e
Former-commit-id: d362e9cb85989f4ea852892bd5722782c11ce2df
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox