GLOBAL MARKETS-OPEC decision knocks oil down, dollar gains

* U.S. crude falls almost 8 percent, Brent also declines* Falling energy shares weigh on global equities; Wall St rises* Dollar mostly strengthens on OPEC decision; bond yields fall(Adds European bond, stock market close)By Herbert LashNEW YORK, Nov 28 (Reuters) - Crude oil tumbled on Friday, knocking down both energy-related shares and currencies after OPEC&aposs decision a day earlier not to cut