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

Add RPC/Websocket calls for:

getdepositscript
createseries
replaceseries
thawseries
This is more API code so I prefer to test these with something like what I wrote in tools/websocket/websocket_test.go. I'll have to adjust that test, of course, but the idea is that we should be testing the API end point here, not unit-testing this.