[CONNECT C++] mdlLevelIterator_setIterateType()

While writing a function to delete unused levels in a model, I called mdlLevelIterator_setIterateType(), passing LEVEL_ITERATE_TYPE_UNUSED_LEVELS, and the resulting iterator only contained USED levels. I changed the type to LEVEL_ITERATE_TYPE_ALL_LEVELS and got, as expected, all levels. Finally, I changed it to LEVEL_ITERATE_TYPE_USED_LEVELS and got the same as the first try - all used levels. I checked the enum values, and LEVEL_ITERATE_TYPE_UNUSED_LEVELS and LEVEL_ITERATE_TYPE_USED_LEVELS have different values, but they both returned the same results...