Add customizable ordering to rules.

Uses jQuery-UI for drag-and-drop ordering.

Note that new rules will be dropped in at the beginning by default.

I'm conflicted about auto-save; I put it in because I kept forgetting to click the save button, but it does seem like overkill.

The screenshot doesn't show it, but it does change your cursor into the universal "four-arrow-cross" that tells the user that they can move the objects.

#135
![rule-drag-and-drop](https://f.cloud.github.com/assets/887446/246292/82adc5e2-8a9a-11e2-9192-a8048dda1421.png)