WIP - Check integration with new btcpy

[belovachap]

@peerchemist @saeveritt

We don't have to merge this, just wanted to make sure the newest btcpy changes didn't break anything. All the tests pass and a few more resolved :)

Not sure what other plans you had for testing btcpy, but at least it works for this one case 🎆

[saeveritt]

Everything looks good. The only thing I see is that the wif property needs to be modified.
to_wif() as per the new btcpy should take the network as an input arg.

    @property
    def wif(self) -> str:
        '''convert raw private key to WIF'''

        btcpy_constants = net_query(self.network).btcpy_constants
        return self._private_key.to_wif(btcpy_constants)

[peerchemist]

@belovachap can you push the new branch with this code? I'd leave it in testing for a while it's a big change.