File_Structure_Test to make sure we don't regress.
According to the PHP docs, the "public" keyword is implied on static
functions, so remove it. Also, require private static functions to
start with an _.
http://php.net/manual/en/language.oop5.visibility.php
clearer about its actions, otherwise we may accidentally blow away an
entire hierarchy when we think we're deleting a single file (there's a
reason why rm won't let you delete dirs that aren't empty!)
Name it "dir" instead of "directory" because apparently "directory" is
already reserved.
Move the delete call out of Items_Controller and into the model. The
model is responsible for keeping state integrity, not the controller.