disambiguate DataItem::c_field from SimulationResult::converted_field

GUI/Model/Data/DataItem.cpp

GUI/Model/Data/DataItem.h

GUI/Model/Data/DataItemUtil.cpp

GUI/Model/Data/IntensityDataItem.cpp

GUI/Model/Data/MaskUnitsConverter.cpp

GUI/Model/Data/SpecularDataItem.cpp

GUI/Model/Device/RealItem.cpp

GUI/Model/Job/JobItem.cpp

GUI/View/Fit/FitObjectiveBuilder.cpp

GUI/View/Loaders/AutomaticDataLoader1DResultModel.cpp

GUI/View/Mask/MaskEditorCanvas.cpp

GUI/View/Mask/MaskResultsPresenter.cpp

GUI/View/Plot2D/IntensityDataCanvas.cpp

GUI/View/Plot2D/IntensityDataFFTPresenter.cpp

GUI/View/Plot2D/IntensityDataWidget.cpp

GUI/View/PlotComparison/FitComparisonWidget.cpp

GUI/View/PlotComparison/FitComparisonWidget1D.cpp

GUI/View/PlotSpecular/SpecularDataCanvas.cpp

GUI/View/PlotSpecular/SpecularPlot.cpp

GUI/View/PlotUtil/ColorMap.cpp