* Add back pointer Item.hub
* Hub.enableItem() -> Item.enable()
* Rename variable i -> idx (i is used for item instances)
* Move Hub.purgeItem() -> Item.purge()
* Move Hub.disableItem() -> Item.disable()
* Move Hub.downloadItem() -> Item.download()
* Move Hub.downloadLatest() -> Item.downloadLatest()
* Move Hub.DownloadDataIfNeeded() -> Item.DownloadDataIfNeeded()
* Move Hub.InstallItem() -> Item.Install()
* Move Hub.RemoveItem() -> Item.Remove()
* Move Hub.UpgradeItem() -> Item.Upgrade()
* store hub items as pointers
* No need to re-add items to the hub if we use pointers
* Fix parameter calling order + regression test