TOWNIE By Andre Dubus III 400 pp. W.W. Norton & Company, $15.95. Acclaimed author Andre Dubus III (House Of Sand And Fog) takes us back with him on a journey through his childhood in the slums of Lynn, Massachusetts all the way up through his development as a young man and then through his battle with his own demons as an adult in this memoir. Dubus provides at times an unflinching take on life in New England, sparing us the smarmy rough-and-tumble portrayal we’ve so often seen in film, and showing us a side of New England we don’t often see – poverty, abuse, and drug culture. The setting of Lynn, Massachusetts could be a stand-in for New York City in the 1970’s with…