Reuters: Actor Robert Redford and other big name clean energy advocates are piling pressure on U.S. President Barack Obama to seize upon the giant Gulf oil spill as a catalyst to steer America clear of its oil addiction. “The Gulf disaster is more than a terrible oil spill,” Redford says in a television ad sponsored by environmental group Natural Resources Defense Council that began airing late Wednesday. “It’s the product of a failed energy policy.” Redford, New York Times columnist …