enh: Add image gradient options to calculate-surface-attributes [Applications]
enh: Add image gradient options to calculate-surface-attributes [Applications]

schuhschuh/MIRTK,stefanpsz/MIRTK,schuhschuh/MIRTK,BioMedIA/MIRTK,BioMedIA/MIRTK,stefanpsz/MIRTK,stefanpsz/MIRTK,BioMedIA/MIRTK,stefanpsz/MIRTK,BioMedIA/MIRTK,schuhschuh/MIRTK,schuhschuh/MIRTK