Remove typedef of MultiLayerCoeff_t, since it's just a vector

Core/Multilayer/DWBADiffuseReflection.h

Core/Multilayer/MatrixFresnelMap.cpp

Core/Multilayer/SpecularMagnetic.cpp

Core/Multilayer/SpecularMagnetic.h

Core/Multilayer/SpecularMatrix.cpp

Core/Multilayer/SpecularMatrix.h

Core/Simulation/SpecularSimulation.cpp

Tests/UnitTests/Core/Fresnel/SpecularMagneticTest.h

Tests/UnitTests/Core/Fresnel/SpecularMatrixTest.h

auto/Wrap/doxygen_core.i