Updates to graphacces.h

The new class definitions are very straightforward.

struct DPEdgeStruct{
  float time;
  }; 
  
struct DPNodeStruct{
  double value;
  double previous_value;
  Gedge *control;
  };

class ACCESS_DPNODESTRUCT : public ACCESS_VOID
{
   public:
     ACCESS_DPNODESTRUCT(){;};
     ~ACCESS_DPNODESTRUCT(){;};
     int equal(Arbent,Arbent);
     ostream& show(ostream&,Arbent);
     void entry(Arbent *,Arbent);     
};
  
class ACCESS_DPEDGESTRUCT : public ACCESS_VOID
{
   public:
     ACCESS_DPEDGESTRUCT(){;};
     ~ACCESS_DPEDGESTRUCT(){;};
     int equal(Arbent,Arbent);
     ostream& show(ostream&,Arbent);
     void entry(Arbent *,Arbent);     
};