NEW YORK (AP) — Shoppers stepped up their spending in May and surpassed expectations as temperatures warmed and gasoline prices cooled. Retail sales rose 0.9%, up from a revised 0.4% gain in April, according to new Commerce Department data released Wednesday. Sales got a boost from generous government tax refunds in both April and May, though economists say that cash cushion is starting to fade. Excluding sales at gas stations, retail sales in May rose 0.7%. Spending was broad-based. Business