House of Echoes by Brendan Duffy Ballentine Books/ Random House, $26.00, 383 pages, ISBN 978-0-8041-7811-2 What do you do when your world gets turned upside down? For most of us the answer is easy, but hard: you start over. And that’s exactly what Ben Tierney, his wife Caroline, and their eight-year-old son Charlie decide to do after novelist Ben’s new book stalls out, Caroline loses her prestigious Wall Street