* method rename: GetInstalledItemsAsString() -> GetInstalledItemNames()
* use path package
* Comments and method names
* Extract method Item.setVersionState() from Hub.itemVisit()
* refact localSync(), itemVisit() etc.
* fix check for cyclic dependencies, with test
* 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