Classification test working now

src/classification/utils.cpp

src/descriptor_identifier/Model/ModelClassifier.cpp

src/descriptor_identifier/SISSO_DI/SISSOClassifier.cpp

src/python/bindings_docstring_keyed.cpp

src/python/descriptor_identifier/SISSOClassifier.cpp

src/utils/math_funcs.cpp

tests/test_classification/test_classification.py