* 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
* Refactor hub URL/branch configuration
* docker: using --force to implement $DISABLE (required for items in collections)
* use pointer receiver for consistency
* csconfig: drop redundant hub information on *Cfg structs
* rename validItemFileName() -> item.validPath()
* Methods on hub object
* updated tests to reduce need of csconfig.Config or global state