[m.i102] Attach RoughnessModel to single rough interfaces (#102) ()

Resample/Processed/ReSample.cpp

Resample/Slice/SliceStack.h

Resample/Specular/ComputeFluxMagnetic.cpp

Resample/Specular/ComputeFluxScalar.cpp

Sample/Interface/LayerRoughness.cpp

Sample/Interface/LayerRoughness.h

Sample/Multilayer/MultiLayer.cpp

Sample/Multilayer/MultiLayer.h

Sample/StandardSample/ExemplarySamples.h

Sample/StandardSample/FeNiBilayerBuilder.cpp

Sample/StandardSample/MagneticLayersBuilder.cpp

Sample/StandardSample/MultiLayerWithNCRoughnessBuilder.cpp

Sample/StandardSample/MultiLayerWithNCRoughnessBuilder.h

Sample/StandardSample/MultiLayerWithRoughnessBuilder.cpp

Sample/StandardSample/MultiLayerWithRoughnessBuilder.h

auto/Examples/fit/specular/Honeycomb_fit.py

auto/Examples/specular/RoughnessModel.py

auto/MiniExamples/fit/specular/Honeycomb_fit.py

auto/MiniExamples/specular/RoughnessModel.py

auto/Wrap/libBornAgainSample.py