Ignore indentation errors in comments
Indentation errors in code and comments use different error codes since pep8 1.6.0 (https://pypi.python.org/pypi/pep8#id3 and https://github.com/jcrocholl/pep8/commit/7b9449d525bcc2c5df4699616d8b75de76a586d4). The attached patch adds the error code for indentation error in comments to the list of ignored error codes.