staging some future refactoring, .h -> hpp, fix for rendering w/ audio

src/anm2/null.hpp

@@ -0,0 +1,20 @@
+#pragma once
+
+#include <string>
+#include <tinyxml2/tinyxml2.h>
+
+namespace anm2ed::anm2
+{
+  class Null
+  {
+  public:
+    std::string name{};
+    bool isShowRect{};
+
+    Null() = default;
+    Null(tinyxml2::XMLElement*, int&);
+    tinyxml2::XMLElement* to_element(tinyxml2::XMLDocument& document, int id);
+    void serialize(tinyxml2::XMLDocument&, tinyxml2::XMLElement*, int);
+    std::string to_string(int);
+  };
+}