The decorations are ready the sales are set and the Black Friday deals will once again start earlier than ever. Welcome to another make-or-break holiday retailing season for discount retailers. Take Wal-Mart Stores (NYSE:WMT) for instance. The giant retailer lost a chunk of its market share to the dollar stores during the recession and finally saw some strong sales growth in the first half of 2012 only to see a slower gain in the third quarter. Now as Wal-Mart tries to ramp up its profit margins it is facing a triple whammy: A potential Thanksgiving strike by employees fears that ...