Bugfix: scantailor-cli doesnt honor color-mode settings from projectfile...

.... It alwas convertes pictures to black and white instead of color

Found when using DIYBookscanner/spreads when manually editing via gui and letting spreads continue running scantailor-cli --start-filter=6 /tmp/spreads.TaZcoK/tmpuNi7DS-0.ScanTailor /tmp/st-outEvBCSO