- Changed the place of hook_theme()

- #326570 by zmove : Save discounts as an array instead of returning single discounted price.
- #326570 by zmove : Return the discount amount instead of returning a discounted product price
- #328111 by zmove : Add an option to display discounts description on the product page
- Changed hook_cart_item() to calculate the discounted price by getting discount informations on the node object instead of calling again uc_discounts_product_discount_price().