Added Cart Predicate functions 'shippingInfoExists' and 'forAllShippingInfos'

With the addition of shippingInfoExists and forAllShippingInfos functions to Cart Predicates you can now construct predicates that match against ShippingInfo on Carts with multiple Shipping Methods.

Changes:

• [API] Added functions shippingInfoExists and forAllShippingInfos to Cart Predicates.