Moved Mesh to core namespace

CMakeLists.txt

examples/fit-model-ceres.cpp

examples/fit-model-simple.cpp

examples/fit-model.cpp

examples/generate-obj.cpp

include/eos/core/Mesh.hpp

include/eos/fitting/closest_edge_fitting.hpp

include/eos/fitting/contour_correspondence.hpp

include/eos/fitting/fitting.hpp

include/eos/morphablemodel/MorphableModel.hpp

include/eos/render/render.hpp

include/eos/render/render_affine.hpp

include/eos/render/texture_extraction.hpp

include/eos/render/utils.hpp

matlab/+eos/+fitting/private/fitting.cpp

matlab/include/mexplus_eos_types.hpp

python/generate-python-bindings.cpp