GLOBAL MARKETS-World stocks up, US dollar down as central bank action eyed

* U.S. Midwest business activity contracts in April; US dollar falls * Fall in euro zone inflation adds to rate cut case * Oil drops on growth worries By Caroline Valetkevitch NEW YORK, April 30 (Reuters) - Stocks on major markets edged higher on Tuesday while the U.S. dollar fell to a two-month low on expectations of further supportive actions by U.S. and European central banks. Investors await the release of the Federal Reserve's policy statement on Wednesday as well as t