Mario: fix modifier deletion

mario/visitors/bounce_visitor.hpp

@@ -6,29 +6,29 @@
 
 class BounceVisitor : public SDLPP::Visitor {
 public:
-    BounceVisitor() {}
-    virtual void visit( const SDLPP::RenderObject &obj ) override;
-    virtual void setFromId( uint64_t id ) override {
+    BounceVisitor() = default;
+    void visit( const SDLPP::RenderObject &obj ) override;
+    void setFromId( uint64_t id ) override {
         from = id;
     }
-    virtual uint64_t getFromId() override {
+    uint64_t getFromId() const override {
         return from;
     }
-    virtual void setVisitorType( uint64_t type ) override {
+    void setVisitorType( uint64_t type ) override {
         _type = type;
     }
-    virtual uint64_t getVisitorType() override {
+    uint64_t getVisitorType() const override {
         return _type;
     }
 
-    bool canBounce() {
+    bool canBounce() const {
         return hits < 2;
     }
 
 private:
     int hits = 0;
-    uint64_t from;
-    uint64_t _type;
+    uint64_t from{};
+    uint64_t _type{};
 };
 
 #endif