Add RGB support for quickflat
Add RGB support for quickflat

smerdis/pycortex,gallantlab/pycortex,smerdis/pycortex,CVML/pycortex,CVML/pycortex,CVML/pycortex,CVML/pycortex,gallantlab/pycortex,smerdis/pycortex,smerdis/pycortex,gallantlab/pycortex,gallantlab/pycortex,gallantlab/pycortex,smerdis/pycortex,CVML/pycortex