never ever change the immutable vertex numbers: otherwise we cannot use
our algorithms from outside with prescribed boundary meshes

-> use MVertex::_index instead

(renamed setNum to forceNum to make sure we don't use setNum by mistake)

enhence statreport

make Show/Hide work with GModel entities

fix crash in remeshUnrecoveredEdges

remove "return" added in orientMeshGFace in revision 1.183

this fixes the surface mesh orientation problem (wrong in 2.4.0)

fix crash in remeshUnrecoveredEdges

fix cl comp pb for embedded verts

rewrote gmsh2DMeshGenerator to make it thread-safe

*** PLEASE TEST THAT THE 2D MESH GENERATORS BEHAVE EXACTLY AS BEFORE ***

fix warnings

remove last statics to make BDS thread-safe

make MElement and MVertex thread-safe by guarding _globalNum

make divide & conquer thread-safe by encapsulating everything into the DocRecord class

oops, should not have committed openmp tests with jf