By DCist Food and Wine Writer Michael Mugmon. Like Hall & Oates, DCist is so close, yet so far away. On Tuesday afternoon, we stopped by our local Subway sandwich shop at 20th and M Streets NW for a footlong meatball sub. When we asked for the two Sub Club stamps we thought we’d earned (one stamp for each six odd inches of grunt), the cashier brusquely informed us that the venerable Sub Club program…