Are we living in the future that Kraftwerk once imagined? It's become something of a cliché to say so, now that the German pioneers of electronic music have been inducted into the art-world canon thanks to an eight-date engagement at the Museum of Modern Art that wraps up Tuesday. But what do we really mean when we say that Kraftwerk predicted our present? Certainly, today's music owes a debt to the music Kraftwerk -- and Kraftwerk alone -- was making back in the 1970s and early '80s. It's compulsory...