TRAVELING KINDMaybe it was just a matter of momentum. It took Emmylou Harris and Rodney Crowell close to four decades to get around to making a duets album after the two first started working together in the mid '70s, when he became a guitarist and frequent songwriter with her Hot Band. But just two years after releasing 2013's Old Yellow Moon, Harris and Crowell have the ball rolling again with The Traveling Kind, another album built around their easy but