Added missing const

app/Operations/CenterOp.cpp

app/Operations/CenterOp.h

app/Operations/CombineColorOp.cpp

app/Operations/CombineColorOp.h

app/Operations/FlipOp.cpp

app/Operations/FlipOp.h

app/Operations/MeanSquaredErrorOp.cpp

app/Operations/MeanSquaredErrorOp.h

app/Operations/PointOp.cpp

app/Operations/PointOp.h

app/Operations/RotateOp.cpp

app/Operations/RotateOp.h

app/Operations/SignalToNoiseOp.cpp

app/Operations/SignalToNoiseOp.h

app/Operations/SplitColorOp.cpp

app/Operations/SplitColorOp.h

app/Operations/ThresholdOp.cpp

app/Operations/ThresholdOp.h

app/Operations/TranslateOp.cpp

app/Operations/TranslateOp.h