Changes in version 0.1.0                        

  - First release.
  - vahtian_freeze() / vahtian_verify() / vahtian_content_hash(): freeze
    a record set into a content-hashed, provenance-stamped, date-locked
    corpus and verify it (tamper-evident).
  - ledger() / ledger_append() / ledger_verify(): a hash-chained,
    tamper-evident audit trail.
  - The canonical format and content hash are byte-identical with the
    Python package 'vahtian', verified by a cross-language golden-hash
    test.