Resolve "Emplace API inconsistent with ProcessorTrackerFeature/Landmark functions"

Closes #191 (closed)

include/core/processor/processor_tracker.h

@@ -97,8 +97,6 @@ class ProcessorTracker : public ProcessorBase
         FeatureBasePtrList new_features_last_;     ///< List of new features in \b last for landmark initialization and new key-frame creation.
         FeatureBasePtrList new_features_incoming_; ///< list of the new features of \b last successfully tracked in \b incoming
 
-        SizeStd number_of_tracks_;
-
     public:
         ProcessorTracker(const std::string& _type,
                          ProcessorParamsTrackerPtr _params_tracker);
@@ -204,16 +202,6 @@ class ProcessorTracker : public ProcessorBase
 
         FeatureBasePtrList& getNewFeaturesListLast();
 
-        const SizeStd& previousNumberOfTracks() const
-        {
-            return number_of_tracks_;
-        }
-
-        SizeStd& previousNumberOfTracks()
-        {
-            return number_of_tracks_;
-        }
-
     protected:
 
         void computeProcessingStep();