moved several files around

Mostly moved classes that became node derivatives into the node/ folder.

app/node/output/track/track.cpp

@@ -55,11 +55,6 @@ Track::Track() :
   track_height_ = kTrackHeightDefault;
 }
 
-Track::~Track()
-{
-  DisconnectAll();
-}
-
 void Track::set_type(const Type &track_type)
 {
   track_type_ = track_type;

app/node/output/track/track.h

@@ -44,7 +44,7 @@ public:
 
   Track();
 
-  virtual ~Track() override;
+  NODE_DEFAULT_DESTRUCTOR(Track)
 
   const Track::Type& type() const;
   void set_type(const Track::Type& track_type);

app/node/output/track/tracklist.cpp

@@ -24,7 +24,7 @@
 #include "node/math/math/math.h"
 #include "node/math/merge/merge.h"
 #include "node/output/viewer/viewer.h"
-#include "project/item/sequence/sequence.h"
+#include "node/project/sequence/sequence.h"
 
 namespace olive {