Unzip artpacks on demand, keep zip, drop user in resulting directory, do not...

Unzip artpacks on demand, keep zip, drop user in resulting directory, do not unzip again if directory already exists.
Don't display [..] when in ansiRoot directory, even if it does nothing.
Added a disallowedFiles[] array.  Files or directories exactly matching fields in this array will not be openable.
Thanks to access_d for testing and suggesting features & changes, even if he is unprofessional and I hate his face.