For the past several weeks I have written about the state of musical theater today, pointing out the emergence of the popular “juke box” musicals and shows based on successful motion pictures.As an old-time pre-baby boomer, pre-Generation X and pre-millennial, I am happy to now report that an old-time musical is being presented at the Goodman Theatre through Aug. 18.“The Music Man,” winner of the 1957 Tony Award for Best Musical, with book, music and lyrics by Meredith Wilson and directed by Mary …