neptune-core:
* add DataDirectory::utxo_transfer_directory_path()
* make DataDirectory serializable
* derive(clap::ValueEnum) for Network
* improve Network doc-comments for use in neptune-cli help.
* Network::RegTest --> Regtest
* impl Add,AddAssign for BlockHeight
* simplify BlockSelector impl
* add Block::genesis_prev_block_digest()
* add trait BlockchainBlockSelector
* make TxInput serializable
* change TxIput::spending_key to unlock_key
* add type alias TxAddressOutput = (ReceivingAddress, NeptuneCoins)
* split UtxoNotifyMethod into Owned and Unowned variants.
* make UtxoNotification serializable
* add OffChainSerialized to utxo notification enums.
* make TxOutput serializable
* add TxOutput::offchain_serialized()
* add UtxoTransferList::utxo_transfer_iter()
* rename TransactionDetails --> TxParams
* rename NeptuneCoins::one() -> one_nau()
* derive clap::ValueEnum for KeyType
* make SpendingKey serializable
* add ReceivingAddress::bech32m_abbreviated()
* make GenerationSpendingKey serializable
* impl bech32m for SymmetricKey with prefix "nsk"
* add UtxoNotifier::Claim variant
* add struct wallet::UtxoTransfer
* prevent dups in WalletState::add_expected_utxo()
* add WalletState::has_expected_utxo()
* add WalletState::find_monitored_utxo()
* add WalletState::find_known_spending_key_for_receiver_identifier()
* add WalletState::prepare_claim_utxo_in_block()
* add WalletState::finalize_claim_utxo_in_block()
* add WalletStatus::synced_unspent_amount()
* cache tip block in ArchivalState.
* add ArchivalState::canonical_block_stream_asc()
* add ArchivalState::canonical_block_stream_desc()
* impl BlockchainBlockSelector for ArchivalState
* impl BlockchainBlockSelector for BlockchainState
* remove BlockchainArchivalState
* add GlobalStateLock::generate_tx_params()
* add GlobalStateLock::send()
* simplify create_transaction()
* log detailed message when storing block.
* add struct TxOutputMeta
* add shared test method mine_block_to_wallet()
* insert tx into mempool in GlobalStateLock::send() rather than main loop.
* add rpc data_directory()
* add rpc generate_tx_params()
* add rpc generate_tx_params_from_tx_outputs()
* add rpc claim_utxo()
* remove rpc send_to_many()
* add rpc test: claim_utxo_owned_before_confirmed()
* add rpc test: claim_utxo_owned_after_confirmed()
* add rpc test: claim_utxo_unowned_before_confirmed()
* add rpc test: claim_utxo_unowned_after_confirmed()

neptune-cli:
* add doc-comment description of every command for help
* remove redundant tip-header command
* renamed own-receiving-address --> next-receiving-address
* next-receiving-address accepts key-type arg
* send accepts optional params: recipient, unowned-utxo-notify-method, owned-utxo-notify-method
* send-to-many accepts same parameters parsed from outputs list.
* send and send-to-many create utxo-transfer file(s) if necessary and
   instructions for sender and recipient.
* improved help-text of send, send-to-many. shows variants of enum params.
* send and send-to-many obtain data_dir from neptune-core.
* added claim-utxo command.
* wallet maintenance commands accept optional data_dir
* --network is now command specific.

cargo.toml:
* add clap feature "string"