Commerce Coupon Credit

Expanding on the commerce coupons module, this module creates a new rules action. This rules action is similar to the one defined in commerce coupon, which creates a coupon line item, but this action additionally checks to see if the coupon is for an amount greater then the order balance. If it is, it only reduces the order by the order total (getting rid of the negative balance issue with commerce coupon). It then sets the coupon to the "credit amount" left over, and adds another use to the coupon, so it may be applied to another order.