GLOBAL MARKETS-Doubts undermine stocks as ECB faces 1 trillion euro question

* Global PMIs dent risk appetite * Europe stocks drop as global sell-off continues * Tokyo stocks hit hard, safe-haven yen, gold benefit * Spotlight on Draghi as ECB meets By Marc Jones LONDON, Oct 2 (Reuters) - World stocks were knocked hard on Thursday after global manufacturing data and an Ebola health scare in the United States spooked markets, sending investors scurrying to the safety of U.S. bonds, the yen and gold. European markets were sucked into the storm befor