added histogram, changed colormap back to color
added histogram, changed colormap back to color

git-svn-id: http://svn.code.sf.net/p/petavision/code/sandbox@6319 7c0444ca-5550-0410-9008-faecdbe78eb5

Former-commit-id: fdf76f51c16036894c75bb82ff7bb8f60c24b95b
dpaiton/OpenPV,PetaVision/OpenPV,dpaiton/OpenPV,dpaiton/OpenPV,dpaiton/OpenPV,dpaiton/OpenPV,PetaVision/OpenPV,dpaiton/OpenPV,PetaVision/OpenPV,dpaiton/OpenPV,PetaVision/OpenPV,PetaVision/OpenPV,dpaiton/OpenPV