Fixed aggressive backup behavior.

Directory blocks now check the action to see if the action triggers a
full directory backup. So far, there are no defined actions that do so,
although the current code suggests a "remove" action would fit the bill.
Directory backups are not necessary on create and copy because copies
expand into file actions, which trigger their own backups.
File touches no longer trigger backups. This mirrors the Directory
change, but includes "create" in the backup triggering actions.