Added session cart.
Added test for BaseAdapter.
Covered test for adapters.
Covered test for views.
Covered tests.
Cosmetics
Cached methods: ulocalized_time and getSessionData.
Refactored
Updated memoize import.
Added dependency to collective.base.
Added collective.base to versions
Added method: shop_path to ShoppingSite adapter.
Updated name of class
Added module.
Added redirection to cart url when cart is empty.
Updated changelog.
Release 0.5.3
Removed BaseAdapter since the class is moved to collective.base package.
Added method to clear cart in session.