Add aria-label to the DFW buttons, props joedolson, fixes #26555

git-svn-id: https://develop.svn.wordpress.org/trunk@27766 602fd350-edb4-49c9-b593-d223f7449a82
Use `wp_parse_id_list()` when parsing `exclude_tree` in `get_pages()`. Add unit tests to ensure a URL string, array with string as value, and array with array as value for `exclude_tree` can be used to specify multiple IDs.

Props cgaffga, roothorick, hakre, tbrams for patches across the years.
Fixes #9153.



git-svn-id: https://develop.svn.wordpress.org/trunk@27767 602fd350-edb4-49c9-b593-d223f7449a82