New functions added on 22/10/2016:
- create_initial_rest_routes
- register_initial_settings
- register_rest_field
- rest_authorization_required_code
- rest_get_avatar_sizes
- rest_get_avatar_urls
- rest_is_boolean
- rest_is_ip_address
- rest_parse_request_arg
- rest_sanitize_boolean
- rest_sanitize_request_arg
- rest_validate_request_arg
- wp_cache_get_last_changed
- wp_custom_css_cb
- wp_get_custom_css
- wp_parse_slug_list