Draft: Resolve "Implementation of new nodes creation"

Closes #454, #318, #364, #449, #381, #376, #208, #485

include/core/processor/track_matrix.h

@@ -121,6 +121,8 @@ class TrackMatrix
     FeatureBasePtr      feature(const SizeStd& _track_id, CaptureBasePtr _cap);
     CaptureBaseConstPtr firstCapture(const SizeStd& _track_id) const;
     CaptureBasePtr      firstCapture(const SizeStd& _track_id);
+    CaptureBaseConstPtr lastCapture(const SizeStd& _track_id) const;
+    CaptureBasePtr      lastCapture(const SizeStd& _track_id);
 
     list<SizeStd> trackIds(CaptureBaseConstPtr _capture = nullptr) const;
 
@@ -128,6 +130,9 @@ class TrackMatrix
     TrackConst trackAtKeyframes(const SizeStd& _track_id) const;
     Track      trackAtKeyframes(const SizeStd& _track_id);
 
+    // Remove snapshots of captures that are being removed from the problem (e.g. when a keyframe is removed)
+    void cleanSnapshots();
+
   private:
     static SizeStd track_id_count_;