Simple grains yield rich breads that range from the mystically light to the substantially chewy. These breads offer incontestable food value and flavor; they will satisfy and delight those sensitive to nutritional concerns. The very act of bread baking itself provides a welcome diversion from the computer screen or office -- and a gratifying result, no matter one's other occupations!          Two sisters, whose family has operated a mill for two generations producing stone-ground flours, bring these recipes from the family and neighbors in West Virginia. Here are more than 180 recipes for a multitude of breads, sweet rolls, international grain dishes, and desserts. Each recipe is explained in thorough detail for a novice as well as an experienced baker.