Possibilities is an apt name for Herbie Hancock’s latest project, a wide-ranging collection of studio collaborations between the jazz legend and a multi-generational lineup of artists, from household names like John Mayer, Sting, Annie Lennox, Christina Aguilera, Paul Simon, Carlos Santana and Trey Anastasio, to serious up-and-comers like Damien Rice, Joss Stone and Raul Midón. For Hancock, whose four-decades-plus career has been a model of fearless boundary stretching, this yearlong effort was