Fix bugs

_ucoinpy_test/documents/test_block.py

ucoinpy/api/bma/blockchain/__init__.py

ucoinpy/api/bma/network/peering/__init__.py

ucoinpy/api/bma/tx/__init__.py

ucoinpy/api/bma/wot/__init__.py

ucoinpy/documents/__init__.py

ucoinpy/documents/block.py

ucoinpy/documents/certification.py

ucoinpy/documents/membership.py

ucoinpy/documents/peer.py

ucoinpy/documents/status.py

ucoinpy/documents/transaction.py