52730: Activation of SMESH fails after GEOM group modification
Fix SMESH_Mesh_i::CheckGeomGroupModif()
52731: Exception at export of SEG3 groups
Fix BUGs concerning Export:
1) Exception at export of the SEG3 group as a separate object.
2) Many formats available in the pop-up menu when several objects selected while only MED and CGNS formats support several meshes in one file.
3) Export of the mesh and its group to the same file results of storage of the group only. Object names are not kept.
