add tick and on_tick event, fix unsaved document prompt, implement TextInput blinking cursor

src/node_dialog_open.h

@@ -50,6 +50,8 @@ class NodeDialogSave : public NodeBorder
 public:
     NodeButton* btn_cancel;
     NodeButton* btn_ok;
+    NodeButton* btn_path;
+    NodeText* working_path;
     NodeTextInput* input;
     std::string selected_path;
     virtual Node* clone_instantiate() const override;