implemented instance binding data usage

This commit changes the way C++ wrapper classes work.
Previously, wrapper classes were merely wrapper *interfaces*.
They used the `this` pointer to store the actual foreign Godot
Object.

With the NativeScript 1.1 extension it is now possible to have
low-overhead language binding data attached to Objects.

The C++ bindings use that feature to implement *proper* wrappers
and enable regular C++ inheritance usage that way.

Some things might still be buggy and untested, but the C++
SimpleDemo works with those changes.

include/gen/VisualScriptSceneNode.hpp

@@ -0,0 +1,38 @@
+#ifndef GODOT_CPP_VISUALSCRIPTSCENENODE_HPP
+#define GODOT_CPP_VISUALSCRIPTSCENENODE_HPP
+
+
+#include <gdnative_api_struct.gen.h>
+#include <stdint.h>
+
+#include <core/CoreTypes.hpp>
+#include <core/Ref.hpp>
+
+#include <VisualScriptNode.hpp>
+namespace godot {
+
+
+class VisualScriptSceneNode : public VisualScriptNode {
+public:
+
+	static void *___get_type_tag();
+	static void *___get_base_type_tag();
+	static inline const char *___get_class_name() { return (const char *) "VisualScriptSceneNode"; }
+	static inline Object *___get_from_variant(Variant a) { godot_object *o = (godot_object*) a; return (Object *) godot::nativescript_1_1_api->godot_nativescript_get_instance_binding_data(godot::_RegisterState::language_index, o); }
+
+	// enums
+
+	// constants
+
+
+	static VisualScriptSceneNode *_new();
+
+	// methods
+	void set_node_path(const NodePath path);
+	NodePath get_node_path();
+
+};
+
+}
+
+#endif