An hors d’oeuvre to whet your appetite for tonight’s debate. Good news for the guy who’s led nearly every poll for seven months: He’s now a slight favorite for the nomination over a guy who doesn’t lead anywhere and is having trouble cracking 15 percent. Donald Trump is the new favorite to win the Republican presidential nomination, Betfair said, less than three weeks before Iowa caucus-goers cast the first votes of the 2016 election.The odds on a Trump victory are 15/8, or 34 percent, putting the billionaire real-estate mogul as favourite in the market for the first time, Betfair...