Pass Type to luax_register_type by pointer instead of reference

Since the type is passed to va_start, and apparently that's undefined behaviour if it's a reference.

<Textmode> the best kind of behavior

--HG--
branch : dynamiccore2

src/modules/image/wrap_ImageData.cpp

@@ -366,7 +366,7 @@ static const luaL_Reg w_ImageData_functions[] =
 
 extern "C" int luaopen_imagedata(lua_State *L)
 {
-	int ret = luax_register_type(L, ImageData::type, w_Data_functions, w_ImageData_functions, nullptr);
+	int ret = luax_register_type(L, &ImageData::type, w_Data_functions, w_ImageData_functions, nullptr);
 
 	luax_gettypemetatable(L, ImageData::type);