TrajectoryBase const qualifier changes

include/core/trajectory/trajectory_base.h

@@ -53,7 +53,7 @@ class TrajectoryBase : public NodeBase, public std::enable_shared_from_this<Traj
 
     public:
         // factors
-        void getFactorList(FactorBasePtrList & _fac_list);
+        void getFactorList(FactorBasePtrList & _fac_list) const;
 
     protected:
         FrameBaseConstIter computeFrameOrder(FrameBasePtr _frame_ptr);

src/trajectory/trajectory_base.cpp

@@ -44,7 +44,7 @@ void TrajectoryBase::removeFrame(FrameBasePtr _frame_ptr)
         updateLastFrames();
 }
 
-void TrajectoryBase::getFactorList(FactorBasePtrList & _fac_list)
+void TrajectoryBase::getFactorList(FactorBasePtrList & _fac_list) const
 {
 	for(auto fr_ptr : getFrameList())
 		fr_ptr->getFactorList(_fac_list);