Modify the look of the coupon code.

This moves coupon code to be better aligned with the cart buttons.
This significantly improves the way things look in alternate
localizations.

It used to look like this:
![coupon-code-bad](https://f.cloud.github.com/assets/764390/276916/e38e4854-90b8-11e2-8839-af0934e69867.png)

And now it looks like this:
![coupon_code_good](https://f.cloud.github.com/assets/764390/276917/e3a3dffc-90b8-11e2-9bd1-8e7d46b13d48.png)

If you're a fan, this change should also be applied similarly to master.