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

Add RPC/Websocket calls for:

getdepositscript
createseries
replaceseries
thawseries
We should definitely strive to make everything unit-testable. Replacing unit-tests with integration tests is IMHO a bad direction and should only be done when unit-testing is impossible, which it rarely is. I think we should invest the time and get the code into a state where it can be unit tested.

Note that I *do* think integrations tests are important too, we need both them and unit-tests.