Ability to list all possible errors and warnings to PEP8 can generate. This would be highly useful when one is interested in using the --select flag and would like to select only certain errors/warnings.
The list can currently be found here: https://github.com/jcrocholl/pep8/wiki/ErrorCodes
This issue is partially related to issue #105.
Include the sample configuration and the list of codes in the documen…
…tation, related to issue #112 and issue #139.
This is in the documentation now.