Require conformance to style standards

[thinkingserious]

Issue Summary

In the CONTRIBUTING.md file there is a section on Style Guidelines & Naming Conventions. Please review and implement a check in Travis CI. If there are any style errors, either fix or create a rule to exclude the error.

Before writing any code, we suggest you review our CONTRIBUTING.md file and propose your solution for discussion here in the comments. Thank you!

Aceptance Criteria

• TravisCI checks that the code conforms to our Style Guidelines & Naming Conventions as defined in our CONTRIBUTING.md file
• tests pass locally, in Travis CI and using Docker

[cmccandless]

This issue is unclear. .travis.yml already runs pycodestyle (formerly known as pep8).

If the requirement is simply that the style is enforced by Travis CI, the above line needs to be moved from the after_script section to the script section.