By¬†SHELLY BANJO No SUV-driving American shopper would be surprised to find 20 lb. sacks of dog chow at a Wal-Mart supercenter. But at an urban minimart that is trying to attract bag-toting pedestrians? Not so much. Wal-Mart is struggling to expand with small stores as it seeks to penetrate big cities and jumpstart its U.S. […] ↓ Read the rest of this entry…