OpenGraph WordPress Plugin

Removed post data if it is password protected entry (content, taxonomies). Props for cris.

Fixed PHP warning when image has no alt. Props for samoreen. Fixed try to set cache for an empty value.

Added check is array for og:image to avoid warning. Props for Charles Smith.

Featured image for single content should be first. Added limit to Pinterest og:see_also. It must be 6 or less.

Added integration with plugin Contextual Related Posts for Pinterest og:see_also tag. Added integration with plugin Related Posts for WordPress for Pinterest og:see_also tag. Improved front page twitter:image integration with Simple SEO Improvements. Refactored and removed code duplicate for twitter:image. Refactored integration with YARPP.