Add shop_cart keyword as alias for cart keyword.
Add hooks before_cart_set_users_id,after_cart_set_users_id,
before_cart_set_sessions_id and after_cart_set_sessions_id.
Update users_id resp. sessions_id in cart on login/logout.
Update prerequisites for Interchange6 and Interchange6::Schema.
Add tests for creating an user and show_states field for country result class.
Also prefer to use plugin keywords.