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 [get](https://docs.python.org/2/library/stdtypes.html#dict.get):
```python
self.nickname = self.settings.get('nickname', "")
```
Treat the following lines similarly.