Provide a nodequeue_save_subqueue_order_alter hook to allow other modules to respond to and affect the sort

Let's try again.

Sure, makes sense.

Actually we could/should call this after nodequeue has done it's work. That way other modules can get involved

1) To do their own processing which might be important for some other reason (like saving where the locks are)
2) They can also change the order around as necessary.

This patch provides that feature I mentioned.

It also lets modules modify the subqueue re-ordering form by adding elements and then passes those along to any module that implements the new nodequeue_save_subqueue_order_alter.

It maintains API consistency for all the current hooks in this area.

I'm calling the new "hook" in a somewhat non-standard way that allows for passing the $nodes by reference. This is actually the new standard way to do it that works with PHP 4.x through 5.3 without throwing errors.

One odd detail to this change:

-  if (count(array_unique($nodes)) < count($nodes)) {
+  if (count(array_unique($nodes, SORT_REGULAR)) < count($nodes)) {

I found with the new practice of including the row data that the comparison had to be "regular" which means that it didn't cast types to something before doing the comparison.