In the new novel “Royal Spin,” a young American politico gets a job at Buckingham Palace, working to help the Royal Family address a raft of unflattering headlines. It’s a classic fish out of water story that also feels completely believable considering that the real-life Palace is currently dealing with some sordid revelations of its own … paging Andrew Mountbatten-Windsor? And the novel has an added patina of authenticity as it’s co-authored by notorious royal watcher Omid Scobie, who had