Bugfix: Properly destroy resource reference script objects

Source/Scripting/SBansheeEngine/Wrappers/BsScriptRRefBase.cpp

@@ -74,6 +74,8 @@ namespace bs
 			MonoUtil::freeGCHandle(mGCHandle);
 			mGCHandle = 0;
 		}
+
+		ScriptObjectBase::_onManagedInstanceDeleted(assemblyRefresh);
 	}
 
 	::MonoClass* ScriptRRefBase::bindGenericParam(::MonoClass* param)