* Fix: Fail fast when initializing volume with Version 0
* Fix: Fail fast when loading unsupported volume version (e.g. 0 or 4)
* Refactor: Use IsSupportedVersion helper function for version validation
Walk needed to be added to NeedleMap and CompactMap, to be able to add WalkKeys and WalkValues to volume. This is needed for iterating through all the stored needles in a volume - this was dump's purpose.