Compute Progress bar

Compute Progress bar

+  virtual double GetProgress() const;
+  double GetProgressByTic() const;
+  int& GetComputeCost() { return _computeCost; }

+  int           _computeCost;     //!< "compute cost" of shapes being Compute()d
+  int           _progressTic;     //!< counter of calls from SMESH_Mesh::GetComputeProgress()
+  double        _progress;        //!< progress of Compute() [0.,1.]