Merge pull request #30 from vtexier/master

duniterpy/documents/certification.py

duniterpy/documents/membership.py

duniterpy/documents/transaction.py

examples/create_and_publish_identity.py

examples/create_public_key.py

examples/request_data.py

examples/save_revoke_document.py

examples/send_certification.py

examples/send_membership.py

examples/send_transaction.py