Most commodities steadied Wednesday after Tuesday's sharp sell-off, but corn tumbled again on a bumper harvest forecast that has sent the grain down almost 10% for the week. The Reuters-Jefferies CRB index settled up a shade on higher metals, sugar, coffee and cocoa, despite the slump in corn and a drop of more than 1% in crude oil, its main component. Commodities drew support as the dollar slipped against the euro and commodity bloc currencies,