[pf1] Simplify API in Powerfield and Histogram context; rm PowerfieldIterator ()

Base/Axis/VariableBinAxis.cpp

Base/Axis/VariableBinAxis.h

Device/Data/DataUtils.cpp

Device/Data/DataUtils.h

Device/Data/Powerfield.h

Device/Data/PowerfieldIterator.h

Device/Histo/Histogram1D.cpp

Device/Histo/Histogram1D.h

Device/Histo/Histogram2D.cpp

Device/Histo/Histogram2D.h

Device/Histo/HistogramUtils.cpp

Device/Histo/HistogramUtils.h

Device/Histo/IHistogram.cpp

Device/Histo/IHistogram.h

Device/InputOutput/DataFormatUtils.cpp

Device/InputOutput/ReadWriteINT.cpp

Device/Mask/DetectorMask.cpp

Device/Resolution/ConvolutionDetectorResolution.cpp

GUI/Model/Data/Data1DViewItem.cpp

GUI/Model/Data/IntensityDataItem.cpp