Add empty hrefs

Empty hrefs allow IE10 to properly focus the elements.
Add comment to hrefs with empty URLs

This should prevent fellow developers from accidentally removing the previous fix for IE 10.
Merge pull request #2032 from opf/fix/15979_tabbing_is_missing_for_wp_details_view_tabs_in_IE_10

15979 Tabbing is missing for WP details view in IE 10