node: merge tooltip into data function

app/node/node.h

@@ -175,11 +175,6 @@ public:
    */
   virtual QString Description() const;
 
-  const QString& ToolTip() const
-  {
-    return tooltip_;
-  }
-
   Folder* folder() const
   {
     return folder_;
@@ -198,7 +193,8 @@ public:
     DURATION,
     CREATED_TIME,
     MODIFIED_TIME,
-    FREQUENCY_RATE
+    FREQUENCY_RATE,
+    TOOLTIP
   };
 
   virtual QVariant data(const DataType &d) const;
@@ -1026,11 +1022,6 @@ protected:
     effect_input_ = input;
   }
 
-  void SetToolTip(const QString& s)
-  {
-    tooltip_ = s;
-  }
-
   void SetFlag(Flag f, bool on = true)
   {
     if (on) {
@@ -1229,8 +1220,6 @@ private:
 
   OutputConnections output_connections_;
 
-  QString tooltip_;
-
   Folder* folder_;
 
   QMap<InputElementPair, ValueHint> value_hints_;