The End of That, the new album by Plants & Animals, brims with the kind of rock ’n’ roll character that’s usually seen as the byproduct of hard living and late-night gigs in dingy bars. It’s there in frontman Warren Spicer’s bourbon-and-ashtray vocals, in electric guitarist Nic Basque’s smoke-belching riffs, in drummer Matt Woodley’s swaggering grooves. But the members of the Montreal trio themselves point to an unlikelier source of inspiration: the study of avant-garde composition.