Actually make exists() useful here. Because of the order in which things are loaded...

Actually make exists() useful here. Because of the order in which things are loaded, we've actually _already_ loaded the metadata prior to calling the constructor. It's safe to assume when making a new ForeignAPIFile that we'll want it to exist at that point. However, we'll default to false as it's safer to assume it doesn't exist and skip ourselves some Http requests. You should probably only be using newFromTitle() anyway :)