Make IsFreeFace() fast, the old implementation of IsFreeFace() is renamed -> IsFreeFa...

Make IsFreeFace() fast, the old implementation of IsFreeFace() is renamed -> IsFreeFaceAdv()

   bool IsFreeFace(  int faceIndex, const SMDS_MeshElement** otherVol=0 ) const;
-  // Check that all volumes built on the face nodes lays on one side
+  // Fast check that only one volume is built on nodes of a given face
+  // otherVol returns another volume sharing the given facet
+
+  bool IsFreeFaceAdv(  int faceIndex, const SMDS_MeshElement** otherVol=0 ) const;
+  // Thorough check that all volumes built on the face nodes lays on one side

+  bool IsPoly() const { return myPolyedre; }