Resolve "Make print() and check() functions from LandmarkBase virtual"

Closes #498

include/core/landmark/landmark_base.h

@@ -160,15 +160,15 @@ class LandmarkBase : public NodeStateBlocks
                              std::ostream& stream,
                              std::string   _tabs = "") const;
 
-    void print(int           depth,        //
-               bool          factored_by,  //
-               bool          metric,       //
-               bool          state_blocks,
-               std::ostream& stream = std::cout,
-               std::string   _tabs  = "") const;
+    virtual void print(int           depth,        //
+                       bool          factored_by,  //
+                       bool          metric,       //
+                       bool          state_blocks,
+                       std::ostream& stream = std::cout,
+                       std::string   _tabs  = "") const;
 
     virtual CheckLog localCheck(bool _verbose, std::ostream& _stream, std::string _tabs = "") const;
-    bool             check(CheckLog& _log, bool _verbose, std::ostream& _stream, std::string _tabs = "") const;
+    virtual bool     check(CheckLog& _log, bool _verbose, std::ostream& _stream, std::string _tabs = "") const;
 
   private:
     void setMap(const MapBasePtr _map_ptr);