Pylint‐Recommended Cleanup

Files touched: `blocks.py`

- Whitespace
- Unused arguments
- Multiple statements on one line
Merge pull request #532 from ouziel-slama/develop

fix sign_tx
Merge pull request #534 from ouziel-slama/develop

get_wallet() API method
More Code Reorganisation

Moved address‐handling functions out of `util.py` into new module,
`address.py`.
More Code Reorganisation

Moved logging and message functionality to new module `logging.py`.
Added a Checkpoint at mainnet Block 334000
Pylint‐Recommended Cleanup

Files touched: `address.py`, `api.py`, `backend.py`
Pylint‐Recommended Cleanup

Files touched: `check.py`, `config.py`
use RPC batch for unconfirmed_transactions()