Rework tests to combine atomic and xmr test cases.
Modify btc interface to support P2WSH_nested_in_BIP16_P2SH
Add coin feature tests to test_btc_xmr.py
No CSV or segwit.
sethdseed requires a fully synced chain, manual intervention required to set a key derived from the master mnemonic.
Requires a pivxd version with a backported scantxoutset command.