Mario: prepartations for multiple moving objects

mario/blocks.hpp

@@ -18,7 +18,7 @@ public:
     void setTool( bool tool = true );
     void setTerrain( bool terrain = true );
     void bounce();
-    virtual void custom_move( int ticks ) override;
+    void custom_move( int ticks ) override;
     void setType( LandType::Value type );
     LandType::Value getType() const;
     virtual void onScrollUp() {}
@@ -27,6 +27,8 @@ public:
         return 0;
     }
     virtual void setData( uint8_t /*UNUSED*/ ) {}
+    // handle own visitor
+    virtual void handleVisitor(SDLPP::Visitor &visitor) {}
     bool hasCoin();
     bool hasMushroom();
     void removeCoin();