Even OutKast's much-maligned Idlewild soundtrack was hardly the train wreck it was made out to be; it was scattershot, yes, but it was filled with interesting ideas, including several that actually worked (compressing 60 years of black American music into a single song on the Cab Calloway-inspired Mighty O, for one thing).So why all this talk of hip-hop being dead, or at the very least, stagnant