owmeta coding standards

Pull requests are required to follow the PEP-8 Guidelines for contributions of Python code to owmeta, with some exceptions noted below. Compliance can be checked with the pep8 tool and these command line arguments:

--max-line-length=120 --ignore=E261,E266,E265,E402,E121,E123,E126,E226,E24,E704,E128

Refer to the pep8 documentation for the meanings of these error codes.

Lines of code should only be wrapped before 120 chars for readability. Comments and string literals, including docstrings, can be wrapped to a shorter length.

Some violations can be corrected with autopep8.