rename README -> README.md; uniform subdirectory name Python/, not

Examples/Python/README.md

Examples/Python/fitting/README.md

...thon/fitting/ex01_BasicExamples/basic_fitting_tutorial.py

...ing/ex01_BasicExamples/basic_fitting_tutorial_data.txt.gz

.../Python/fitting/ex01_BasicExamples/consecutive_fitting.py

.../Python/fitting/ex01_BasicExamples/minimal_fit_example.py

...s/Python/fitting/ex01_BasicExamples/minimizer_settings.py

...s/Python/fitting/ex02_AdvancedExamples/find_background.py

.../Python/fitting/ex02_AdvancedExamples/fit_along_slices.py

...es/Python/fitting/ex02_AdvancedExamples/fit_with_masks.py

...Python/fitting/ex02_AdvancedExamples/multiple_datasets.py

...es/custom_objective_function/custom_objective_function.py

..._ExtendedExamples/experiment_at_galaxi/fit_galaxi_data.py

..._ExtendedExamples/experiment_at_galaxi/galaxi_data.tif.gz

...3_ExtendedExamples/experiment_at_galaxi/sample_builder.py

.../ex03_ExtendedExamples/external_minimizer/lmfit_basics.py

...xtendedExamples/external_minimizer/lmfit_with_plotting.py

...tting/ex03_ExtendedExamples/specular/FitSpecularBasics.py

...ng/ex03_ExtendedExamples/specular/FitWithUncertainties.py

...ExtendedExamples/specular/RealLifeReflectometryFitting.py