v1.1.0

Identifier metadata is now loaded lazily from EZID (#23)

• The local metadata is cleared after persisting (create/mint or modify)
  and reloaded only on subsequent access.
• The #metadata reader method provides a boolean refresh parameter
  (default: true) which can be used to bypass the reload. This may
  be useful in testing scenarios.

Internal implementation details of Ezid::Metadata were also changed
without public API impact (the class itself is documented as
private).