Bug 6796 adds the ability to define library opening hours for each branch. It does not, however, respect weekday closed days as defined in the Calendar page. We should expose that detail from the libraries interface, including in the summary table, details view and edit form. I believe this would be best achieved by migrating the weekly closed days from repeatable holidays into the new library_hours table and thus making it available via the existing library_hours embed in the API. This makes it trivial to display the open/closed state in the api driven datatable as well as on the view and edit pages. We should continue to support displaying and editing these weekly closed days from the calendar too, however.