/**
* @brief Remove orphaned database entries
+ * @param integer $stage What should be deleted?
+ *
+ * Values for $stage:
+ * ------------------
+ * 1: Old global item entries from item table without user copy.
+ * 2: Items without parents.
+ * 3: Orphaned data from thread table.
+ * 4: Orphaned data from notify table.
+ * 5: Orphaned data from notify-threads table.
+ * 6: Orphaned data from sign table.
+ * 7: Orphaned data from term table.
+ * 8: Expired threads.
+ * 9: Old global item entries from expired threads
*/
function remove_orphans($stage = 0) {
global $db;