code: use macros for default node functions

Easier to maintain

app/node/output/track/track.cpp

@@ -66,11 +66,6 @@ const Track::Type& Track::type() const
   return track_type_;
 }
 
-Node *Track::copy() const
-{
-  return new Track();
-}
-
 QString Track::Name() const
 {
   if (track_type_ == Track::kVideo) {

app/node/output/track/track.h

@@ -45,13 +45,11 @@ public:
 
   Track();
 
-  NODE_DEFAULT_DESTRUCTOR(Track)
+  NODE_DEFAULT_FUNCTIONS(Track)
 
   const Track::Type& type() const;
   void set_type(const Track::Type& track_type);
 
-  virtual Node* copy() const override;
-
   virtual QString Name() const override;
   virtual QString id() const override;
   virtual QVector<CategoryID> Category() const override;