0.9.0-rc4

• Add routes to the vault client for KYC attestations (ed2da574)
• Currency: add show_interest flag to show or hide interest in Currency.to_human() and Currency.to_json() Example use in tests
• Configurable maxAttempts for transaction submission (d107092)
• Binformat: added missing TransactionResult options (6abed8d)
• Fix: Amount.to_human() round when given precision (033257b)
• Fix: change handling of requestLedger options (57b7030)
• Breaking change: make maxLoops in seed.get_key optional. Example use in tests (23e473b)