Implement ``ICartDataProvider.include_shipping_costs`` on ``CartDataProviderBase`` using ``bda.plone.shipping.interfaces.IShippingItem.shipping`` flag for calculation.
Add ``bda.plone.cart.cart_item_shippable`` utility. Add ``ICartDataProvider.max_artice_count`` attribute and implement in ``CartDataProviderBase``.
Move ``bda.plone.cart.browser.CURRENCY_LITERALS`` to ``bda.plone.cart.CURRENCY_LITERALS``.