Merge branch 'develop' into feature/checkpointing

doc/userdoc.org

src/algebra/TinyMatrix.hpp

src/algebra/TinyVector.hpp

src/language/modules/MathModule.cpp

src/language/utils/EmbeddedDiscreteFunctionMathFunctions.cpp

src/language/utils/EmbeddedDiscreteFunctionMathFunctions.hpp

src/scheme/DiscreteFunctionP0.hpp

tests/test_BuiltinFunctionProcessor.cpp

tests/test_DiscreteFunctionP0.cpp

tests/test_EmbeddedDiscreteFunctionMathFunctions1D.cpp

tests/test_MathModule.cpp

tests/test_TinyMatrix.cpp