Dancefloor-oriented Western Swing is usually cited as the nexus at which country and jazz meet most naturally, but a gentler intertwining of the two genres has long been at work in the music of artists from Willie Nelson to Norah Jones. That’s why Patty Griffin and Nickel Creek’s Sara Watkins fit right alongside idiosyncratic pop singers like Fiona Apple and Sam Phillips, among others, on this tribute to late composer and jazz pianist Cy Coleman.