Merge branch 'master' of /home/untereiner/CGoGN
* 'master' of /home/untereiner/CGoGN: SubdivisionClassic return a centerDart correct template Orbit et IHM3 coarsen mesh bug correction : mr dart duplication in container few changes in Multiresolution managing begin volumetric progressive meshes - adding multilevel extrusion to importMeshExtrud - volumetric decimation