Refs #9313 all pixels for histograms
Refs #9313 change for summing WISH data
Revert "Refs #9313 change for summing WISH data"

This reverts commit a7fb91ded37824d7525bb078a9fb463976909596.
Refs #9313 changes for wish data with more than one pixel per spectra
Refs #9313 style changes
Merge remote-tracking branch 'origin/feature/9313_SmoothNeighbours_new_option'