Replaced atof and atoi inside 3MF attribute parsing with fast_float::from_chars and boost::spirit that are faster.
Replaced atof and atoi inside 3MF attribute parsing with fast_float::from_chars and boost::spirit that are faster.

prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r,prusa3d/Slic3r