Examples executable; improved update script

Examples/fit51_Basic/basic_fitting_tutorial.py

Examples/fit51_Basic/consecutive_fitting.py

Examples/fit51_Basic/minimal_fit_example.py

Examples/fit51_Basic/minimizer_settings.py

Examples/fit52_Advanced/find_background.py

Examples/fit52_Advanced/fit_along_slices.py

Examples/fit52_Advanced/fit_with_masks.py

Examples/fit52_Advanced/multiple_datasets.py

Examples/fit53_CustomObjective/custom_objective_function.py

Examples/fit54_ExternalMinimizer/lmfit_basics.py

Examples/fit54_ExternalMinimizer/lmfit_with_plotting.py

Examples/fit55_SpecularIntro/FitSpecularBasics.py

Examples/fit55_SpecularIntro/FitWithUncertainties.py

Examples/fit55_SpecularIntro/PolarizedSpinAsymmetryFit.py

Examples/fit55_SpecularIntro/RealLifeReflectometryFitting.py

Examples/fit56_SpecularAdvanced/Honeycomb_fit.py

Examples/fit56_SpecularAdvanced/Pt_layer_fit.py

Examples/fit61_Galaxi/fit_galaxi_data.py

Examples/scatter2d/ApproximationDA.py

Examples/scatter2d/ApproximationLMA.py