mv getter implementations to headers

GUI/View/Canvas/MaskEditorActions.cpp

GUI/View/Canvas/MaskEditorActions.h

GUI/View/Dock/DockWidgetInfo.cpp

GUI/View/Dock/DockWidgetInfo.h

GUI/View/Instrument/DistributionSelector.cpp

GUI/View/Instrument/DistributionSelector.h

GUI/View/Main/MainWindow.cpp

GUI/View/Main/MainWindow.h

GUI/View/Sample/SampleListing.cpp

GUI/View/Sample/SampleListing.h

Sample/Aggregate/InterferenceHardDisk.cpp

Sample/Aggregate/InterferenceHardDisk.h

Sample/Material/IMaterialImpl.cpp

Sample/Material/IMaterialImpl.h

Sample/Particle/Particle.cpp

Sample/Particle/Particle.h

Sample/Shapes/IShape3D.cpp

Sample/Shapes/IShape3D.h