"School Pictures," Milo Cramer's last New York show, a solo musical, was wildly inventive, hilarious funny, and extremely insightful about the New York education system, based on his own experiences as a tutor. Unfortunately, his new musical show again premiering at Playwrights Horizons seems to be out of his comfort zone though he has been a fan of musicals for years. "No Singing in the Navy" is a three-character re…