CORRECTED-COMMODITIES-Mostly down for April after brutal mid-month selloff

(Corrects Brent's Tuesday close and milestone for monthly loss, para 11) * Copper down 7 pct for April, sharpest drop since May 2012 * Brent oil also off 7 pct on month, biggest drop since May * Gold loses 8 pct for April, sharpest slide since December By Barani Krishnan NEW YORK, April 30 (Reuters) - Oil and copper fell on Tuesday, finishing April with the largest monthly declines in nearly a year, and gold slipped too on uncertainty whether U.S. and European central banks