Repair and modernize examples

Examples/fit55_SpecularIntro/FitWithUncertainties.py

Examples/fit56_SpecularAdvanced/Pt_layer_fit.py

Examples/specular/BeamAngularDivergence.py

Examples/specular/BeamFullDivergence.py

Examples/specular/TOFRWithResolution.py

Examples/specular/TimeOfFlightReflectometry.py

Examples/varia/AccessingSimulationResults.py

Examples/varia/AllFormFactorsAvailable.py

Examples/varia/AxesInDifferentUnits.py

Examples/varia/BasicPolarizedReflectometry.py

Examples/varia/CustomFormFactor.py

Examples/varia/DepthProbe.py

Examples/varia/FindPeaks.py

Examples/varia/GratingMC.py

Examples/varia/Interference1DLattice.py

Examples/varia/LargeParticlesFormFactor.py

Examples/varia/OffSpecularSimulation.py

Examples/varia/PolarizedNoAnalyzer.py

Examples/varia/PolarizedNonperfectAnalyzerPolarizer.py

Examples/varia/PolarizedSANS.py