use double2d_t everywhere

Device/Analyze/Fourier.cpp

Device/Analyze/Peaks.cpp

Device/Data/DataUtil.cpp

Device/Data/DataUtil.h

Device/Data/Datafield.cpp

Device/Data/Datafield.h

Device/IO/ReadReflectometry.cpp

Device/IO/ReadWrite2DTable.cpp

Device/Resolution/ConvolutionDetectorResolution.cpp

Fit/Adapter/MinimizerAdapter.cpp

Fit/Minimizer/MinimizerResult.cpp

Fit/Param/Parameters.cpp

Fit/Param/Parameters.h

Fit/Residual/ResidualFunctionAdapter.h

GUI/View/Realspace/RealspaceBuilder.cpp

GUI/View/Realspace/RealspaceBuilder.h

Img3D/Build/ParacrystalLatticePositions.cpp

Img3D/Build/ParacrystalLatticePositions.h

Img3D/Build/PositionBuilders.cpp

Img3D/Build/PositionBuilders.h