Lists all items of a directory (folders first, then files, each sorted by name).

• If oid equals the current object ID of the directory, the string uptodate is returned instead of the list.
• Lock fields (is_locked, lock_owner, lock_owner_name, lock_time, locked_by_me) are only returned for files.
• Items with folder permission invisible are not listed.
• Response headers: oid (object ID of the directory) and dir_perm (permission of the current user on it).