1.0.0-beta2

Added

• Testing\Contract\*ContractTests: every store contract is also a trait,
  for hosts whose test cases must extend a framework base class (Testbench,
  KernelTestBase) and so cannot extend the abstract contract; the abstract
  class is now the trait on a bare TestCase, so the two cannot drift.

Changed

• LogisticsEventStore states that every event it receives carries
  cargo:eventDate (the server and the checked builder both refuse one
  without), so stores need no semantics for date-less events.

• A status-change notification for an action request over several logistics
  objects (an access delegation, typically) no longer names an arbitrary first
  object in api:hasLogisticsObject, whose cardinality is at most one; it
  names none and the request in api:isTriggeredBy lists them all (spec
  question 32, IATA-Cargo/ONE-Record#437). Type subscriptions keep matching
  declared @type values only, now recorded as spec question 31
  (IATA-Cargo/ONE-Record#412).