Adds Yoast SEO meta support

Added

Exposes new data into endpoint

• yoast_wpseo_facebook_title aka yoast_wpseo_opengraph-title
• yoast_wpseo_facebook_description aka yoast_wpseo_opengraph-description
• yoast_wpseo_facebook_type
• yoast_wpseo_facebook_image aka yoast_wpseo_opengraph-image
• yoast_wpseo_twitter_title
• yoast_wpseo_twitter_description
• yoast_wpseo_twitter_image
• yoast_wpseo_social_url
• yoast_wpseo_website_name
• yoast_wpseo_company_or_person
• yoast_wpseo_person_name
• yoast_wpseo_company_name
• yoast_wpseo_company_logo
• yoast_wpseo_website_name
• yoast_wpseo_social_defaults

Changed

• READEME.md to include new info.

Updated

• Cleaned and PHPCS linted plugin.