Apply autopep8 formatting to Couchbase Python project

Consistent formatting of the Python SDK should be implemented. In the future, the ideal move will be to use black as the client's formatter. However, with needed support for Python 3.5 (and with black still being in beta), autopep8 will be used in the interim.

This task is to mark the initial formatting of the entire Python project using autopep8.

NOTE: It is not that black cannot be used with Python 3.5, it is that black will allow a comma after the last item in a list or the last parameter in a function. Python 3.5 does not allow a comma after the last parameter of a function. AFAIK, one cannot specify to black to not allow this behavior, it is inferred upon inspecting the file being formatted. Since too many files need formatting applied to be able to handle this scenario, autopep8 it is (for now ).