WASHINGTON (Reuters) -The U.S. will make a push of more than a hundred million in additional funding to respond to the conflict in Sudan as Washington seeks to spur international response at a donor conference on the humanitarian crisis this month, the U.S. Special Envoy to the North African country said on Wednesday. Special Envoy Tom Perriello said he hopes that partners around the world will put greater priority on the Sudanese civil war and that more countries will step up at a donor confere