Added a return to the addCartItem function to return the cartItem object that has been produced. Reason: I want access to the cart item id of the freshly created cart item and without this there is no way to obtain the id of the freshly created item.
Merge pull request #1 from shipleyr/feature/add-item-to-cart/return-cart-item

Added a return to the addCartItem function to return the cartItem object...