message: Add comment explaining EvalIntegrated
diff: @@ -1986,6 +1986,9 @@ public:
  void Eval(const double x, Vector &u) const;
  void Eval(const double x, Vector &u, Vector &d) const;
  void Eval(const double x, Vector &u, Vector &d, Vector &d2) const;
  + /// Evaluate the "integrated" basis, which is given by the negative
  + /// partial sum of the corresponding closed basis derivatives. The closed
  + /// basis derivatives are given by @a d, and the result is stored in @a i.
  void EvalIntegrated(const Vector &d, Vector &i) const;
  bool IsIntegratedType() const { return etype == Integrated; }
  ~Basis();
  