Untested cart discount draft without breaking backwart compatibility.
Merge branch 'cart-discounts-m' into cart-discount

Conflicts:
	java-client/src/main/java/io/sphere/client/shop/model/AbsoluteDiscount.java
	java-client/src/main/java/io/sphere/client/shop/model/CartDiscount.java
	java-client/src/main/java/io/sphere/client/shop/model/CartDiscountTargetPredicate.java
	java-client/src/main/java/io/sphere/client/shop/model/DiscountCode.java
	java-client/src/main/java/io/sphere/client/shop/model/DiscountCodeState.java
	java-client/src/main/java/io/sphere/client/shop/model/DiscountCodeWithState.java
	java-client/src/main/java/io/sphere/client/shop/model/DiscountValue.java
	java-client/src/main/java/io/sphere/client/shop/model/DiscountedLineItemPortion.java
	java-client/src/main/java/io/sphere/client/shop/model/DiscountedLineItemPrice.java
	java-client/src/main/java/io/sphere/client/shop/model/LineItem.java
	java-client/src/main/java/io/sphere/client/shop/model/LineItemContainer.java
	java-client/src/main/java/io/sphere/client/shop/model/LineItemsTargetPredicate.java
	java-client/src/main/java/io/sphere/client/shop/model/RelativeDiscount.java
	java-client/src/main/java/io/sphere/client/shop/model/ShippingTargetPredicate.java