LONDON (Reuters) - The rapid rally in world markets finally paused for breath on Thursday, as traders waited to hear how much more stimulus the European Central Bank plans to shovel out to address the coronavirus slump.The ECB is expected to pump in another 250-500 billion euros for the cause, but after weeks of sharp gains for stocks, oil and confidence-sensitive currencies, investors were taking the chance to lock in some profit.Asian stocks stalled at a two-month high, London , Frankfurt ,..