+ some fixes for ~/salome/Files/Studies_FROM_BUGS/VL_Usecase2.hdf
1) Prevent negative volumes caused by smooth on curvature
2) Add EDGEs to smooth in updateNormals()
3) Fix too high _stepSize causing failure of smoothing on FACEs
4) Correct finding EDGEs needing smooth
5) Fix AddShapeToSmooth(), FindIntersection(), updateNormals(), SegTriaInter()