Feature 10432
[+] Added txHashIsUsedOutItemHash function to the Ledger object. Added a usedBy attribute to all OUT item wrappers, which will return either None or a Hash to the transaction that uses the given output.
[+] Added txHashIsUsedOutItemHash function to the Ledger object. Added a usedBy attribute to all OUT item wrappers, which will return either None or a Hash to the transaction that uses the given output.