Three stars for new Lookingglass Theatre Company musicalThe loss of some 1,500 souls when the RMS Titanic sank in 1912 has been memorialized, if that's the right word, with a century of narrative re-creation, a hit movie, countless documentaries, a Broadway musical, a Celine Dion ballad, a permanent tourist replica in Pigeon Forge, Tenn., and peripatetic exhibits of artifacts.