WordPress VIP Compliance

[bcampeau]

This is ready for you to test and review. Once you sign off that nothing is broken, we can submit the plugin to VIP. Some key highlights of what was done here with helpful links for future maintenance:

• Updated all code formatting to meet WordPress coding standards (https://make.wordpress.org/core/handbook/coding-standards/)
• Added sanitization of all input values (https://vip.wordpress.com/documentation/code-review-what-we-look-for/)
• Added output escaping for all values (https://vip.wordpress.com/2014/06/20/the-importance-of-escaping-all-the-things/)
• Made the plugn i18n compatible (https://make.wordpress.org/polyglots/handbook/)
• Consolidated all constants
• Removed add_option calls that were running on every page view and moved the logic to the config form to set default values.
• Completely rewrote the results page to use underscores templates. Direct HTML output from Javascript is considered non-output safe.

Please let us know if you have any questions and if you run into issues during testing. I would suggest submitting any updates you make via pull requests back to your master branch so we can review them up to the point of VIP submission to ensure everything stays in line with coding standards.

Thanks.