bug fix: orientation of face vertices of 4th order tetrahedra

corrected bug for higher order mappings in post views (supports q up to 4)

Bug fix to getNumMeshElements(unsigned*)

   1) this removes the asymmetry in all the routines involving mesh
      elements associated with points

   2) it makes it possible to use point-based datasets in the
      model-based post-processing module

  **********************************************************
    PLEASE TEST --- ESPECIALLY THE INPUT/OUTPUT ROUTINES!
  **********************************************************

* made GModel::getEntities() more efficient and generalized its use

- more "const char *" fixes