unify local var name sample <- multi_layer etc

Doc/PhysicsManual/fig/drawing/Green.py

Examples/anaklasis/calculate_lipid_multilayer.py

Examples/bayesian/likelihood_sampling.py

Examples/fit/scatter2d/consecutive_fitting.py

Examples/fit/scatter2d/expfit_galaxi.py

Examples/fit/scatter2d/minimizer_settings.py

Examples/fit/scatter2d/multiple_datasets.py

Examples/fit/specular/FitSpecularBasics.py

Examples/fit/specular/Pt_layer_fit.py

Examples/fit/specular/RealLifeReflectometryFitting.py

Examples/scatter2d/CustomFormFactor.py

Examples/scatter2d/CylindersInAverageLayer.py

Examples/scatter2d/FindPeaks.py

Examples/scatter2d/GratingMC.py

Examples/scatter2d/LargeParticlesFormFactor.py

Examples/scatter2d/PositionVariance.py

Examples/scatter2d/RectangularGrating.py

...s/scatter2d/disabled/Interference2DLatticeSumOfRotated.py

Examples/specular/PolarizedNonperfectAnalyzerPolarizer.py

Examples/specular/PolarizedSpinAsymmetry.py