1. Ditch in-house block repo, and use btcd blocks database.
2. Commands switch from args to flags.
3. Revive chain recording and replaying, which will be part of CI pipeline.
4. Refactor cleanup the CLI skeletons.
5. Support DataDir, and testnet/regtes (not tested yet).
TODOs:
1. Remove hardcoded test/development params, and pass them from flags.
2. Make output more sensible.
3. Add debug level flag.
4. Add MerkleTrie implementation switch.
5. Refactor periodic progess/status reporting for long run-time tasks.
...
