Add HD Wallet integration (temporary and hacky!!!)

Add RPC/Websocket calls for:

getdepositscript
createseries
replaceseries
thawseries
I personally see think that's a little too much abstraction as we really aren't doing much in these functions, but I see your point. I don't think we should pass the btcws cmd object, though. We should pass the components separately.

I disagree that integration tests only need to check that the API functions are exposed. Given that this is a public API, it's imperative that we check for the positive case and published error paths at a minimum..