PEP8 openbazaar.py through ws.py

PEP8 clean up 3 of 3.  Orders.py has some very deeply nested dictionaries which necessitate long lines.  This situation may suggest minor future refactoring of the affected methods.
Use formatting:
```python
notary_data_json = '{%s' % (
    offer_data[notary_data_index:end_of_notary_index]
)
```