Create signed atomic swap transaction object ready to be published

[trojkat]

>> my_address = 'mg9sDLhfByfAWFo4zq3JZ7nsLfsN59XPue'
>> bob_btc_address = 'n31og5QGuS28dmHpDH6PQD5wmVQ2K2spAG'
>> outpoints = [
    {
        'txid':'fdb89b980168f04cd52f6044d210a3bc37788ea26133bd74deabfa0272e06d29',
        'vout': 2,
        'value': 0.02,
        'scriptPubkey': 'g617578ac49adb77442fdbb454812bca43f324c9931d93',
    },
    {
        'txid':'abf1a090b046001f31cfacdc1db064eeb465863698c13a7a7b1f5acdf234804a',
        'vout': 0,
        'value': 0.05,
        'scriptPubkey': 'a91432d272ce8a9b482b363408a0b1dd28123d59c63387',
    },
]
>> btc_swap = btc_network.initiate_atomic_swap(sender_address=my_address, recipient_address=bob_btc_address, value=1, outpoints=outpoints, private_key='xxx')
>> btc_swap.sign(private_key, passphrase)