A stronger dollar and weak demand prospects pressured commodities Tuesday, with sugar and cocoa falling to their lowest levels since August and oil, metals and grains all down from the previous session. The 19-commodity Reuters-Jefferies CRB index, which ended a touch lower on Monday, fell 0.7% as renewed fiscal worries over the euro zone led to risk aversion that pushed the dollar higher. A stronger dollar usually hits demand for commodities, as