Process Locking on OS X

On Windows *and OS X*, use `socket.AF_INET` instead of `socket.AF_UNIT`.

Closes #529.
hex string in blocks.previous_block_hash
Merge pull request #531 from ouziel-slama/develop

hex string in blocks.previous_block_hash
Pylint‐Recommended Cleanup

Files touched: `counterparty-cli.py`, `counterpartyd.py`

- Removed unused imports.
- Whitespace
- Indentation
- Multiple statements on one line
allow manually providing pubkeys for multi‐sig (fixes #413)