In an image bound to go down in history, every living U.S. president came together at the White House on Wednesday to hash over the world’s challenges with the president-elect. There they stood, shoulder-to-shoulder in the hails-hottie-picksOval Office: George H.W. Bush, Obama, George W. Bush, Bill Clinton and Jimmy Carter.  “This is an extraordinary gathering,” Obama said, looking plenty at ease in the humbling office that will soon be his.  “All the gentlemen here understand both the pressures and possibilities of this office,” Obama said. “And for me to have the opportunity to get advice, good counsel and fellowship with these individuals is extraordinary. And I’m very grateful to all of them.”  Bush, blistered without mercy by Obama during the campaign season, played the role of gracious host.  “All of us who have served in this office understand that the office transcends the individual,” Bush said as Obama nodded in thanks. “And we wish you all the very best. And so does the country.”  It was a moment of statesmanship that tends to happen when presidents get together, no matter how bitter their previous rivalries. In a photo opportunity that lasted less than two minutes, Carter, Clinton and the senior Bush smiled but said nothing. They deferred to the nation’s incoming and outgoing leaders.  Later in the day, the president-elect praised Bush as “incredibly gracious” and credited the president and his staff with making the transition “as smooth as any we’ve seen in history.” In an interview with CNBC, Obama said the presidents gave him good counsel not only on specific issues but also on raising a family in the White House. The Obamas have two daughters, Malia,