Nevermore ***1/2
       By: Paulanne SimmonsWhen a writer focuses on the macabre as much as Edgar Allan Poe did, it's inevitable that readers will try to discover what caused such a fixation. In Poe's case, there are indeed many unfortunate events that might have contributed to his melancholy disposition. And Jonathan Christenson, who wrote the book and lyrics, and composed the music for Nevermore: The Imagi…