Update TODO.md

Import/TODO.md

@@ -6,6 +6,9 @@
     * **Workflow to C++ code generation with hint**.
         * Types and other symbols, which are reported not supported in C++, cannot be used.
         * Generate reflection code, protected by VCZH_DEBUG_NO_REFLECTION.
+        * Add Reference as one of the TypeInfoHint (for GacUI's event)
+        * Remove `IEventInfo::ICpp`, add `vl::reflection::cpphelper::EventHelper`
+        * Add helpers for argument accessing, `vl::Func<T>` converting and result accessing
 
 ## Comming Soon
 * GacUI