[field2] Powerfield now inherits from IField; new c'tors ()

Base/Types/OwningVector.h

Device/Data/Powerfield.cpp

Device/Data/Powerfield.h

Device/Detector/IDetector2D.cpp

Device/Histo/Histogram1D.cpp

Device/Histo/Histogram2D.cpp

Device/Histo/Histogram2D.h

Device/Histo/IHistogram.cpp

Device/Histo/IHistogram.h

Device/Histo/SimulationResult.cpp

Device/Histo/SimulationResult.h

Device/Mask/DetectorMask.cpp

Device/Mask/DetectorMask.h

GUI/Model/Data/DataProperties.cpp

GUI/Model/Data/DataProperties.h

GUI/Model/Data/DataPropertyContainer.cpp

GUI/View/Mask/MaskResultsPresenter.cpp

GUI/View/PlotSpecular/SpecularPlot.cpp

Tests/PyUnit/histogram2d.py

Tests/Unit/Device/PowerfieldIteratorTest.cpp