nodes: moved hashing to nodes so they can override behavior if they wish

app/node/node.h

@@ -362,6 +362,8 @@ public:
   const QString& GetLabel() const;
   void SetLabel(const QString& s);
 
+  virtual void Hash(QCryptographicHash& hash, const rational &time) const;
+
 protected:
   void AddInput(NodeInput* input);
 
@@ -373,6 +375,8 @@ protected:
 
   virtual void SaveInternal(QXmlStreamWriter* writer) const;
 
+  virtual QList<NodeInput*> GetInputsToHash() const;
+
 public slots:
 
 signals: