DARK MATTEREarly in his career, Randy Newman used to regularly puzzle over his lack of commercial success, seemingly unaware that his trademark combination of New Orleans piano and wildly unreliable narrators was hardly a sure path to the Hit Parade. Decades later, Newman has found a side door to fame and wealth as a composer of film scores and likeable theme tunes for Pixar features. As a consequence, the man who created dark masterpieces like 12 Songs, Sail