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

Add RPC/Websocket calls for:

getdepositscript
createseries
replaceseries
thawseries
I can empathize with you on this one, but I also think being consistent
is important and in this case it allows us to more easily see what went
wrong with a test. Not to mention that we should be consistent with the
codebase we're working on, which seems to follow the recommended order.