update checkbox icons, clear redo actions when cleaning memory

src/action.cpp

@@ -52,6 +52,8 @@ void ActionManager::clear()
 {
     while (!I.m_actions.empty())
         I.m_actions.pop();
+    while (!I.m_redos.empty())
+        I.m_redos.pop();
     I.m_memory = 0;
     //LOG("History: %.2f KB", I.m_memory / 1024.f);
     App::I.update_memory_usage(I.m_memory);

src/node_checkbox.h

@@ -10,7 +10,7 @@ public:
     NodeBorder* m_outer;
     NodeBorder* m_inner;
     NodeImage* m_icon;
-    std::string m_icon_path;
+    std::string m_icon_path = "data/ui/check-v.png";
     bool checked = false;
     virtual Node* clone_instantiate() const override;
     virtual void clone_children(Node* dest) const override;