Resolve "ProcessorTracker compatible with preprocessing and other processors"

Closes #309 (closed)

include/core/processor/processor_tracker.h

@@ -103,6 +103,7 @@ class ProcessorTracker : public ProcessorBase
         CaptureBasePtr incoming_ptr_;           ///< Pointer to the incoming capture being processed.
         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
+        FeatureBasePtrList known_features_last_; ///< list of the known features in previous captures successfully tracked in \b last
         FeatureBasePtrList known_features_incoming_; ///< list of the known features in \b last successfully tracked in \b incoming
         int _dim;