EARLY SATURDAY AFTERNOON the man who had intro-duced himself as Oliver took Ginny to several shops on MadisonAvenue above 70th Street to buy her what he called an appropri-ate outfit.For an hour and forty-five minutes she modeledclothes,watching with critical interest her image in the three-way mirrors,unable to decide if this was one of her really good EARLY SATURDAY AFTERNOON the man who had intro-duced himself as Oliver took Ginny to several shops on Madison Avenue above 70th Street to buy her what he called an appropri-ate outfit. For an hour and forty-five minutes she modeledclothes, watching with critical interest her image in the three-way mirrors, unable to decide if this was one of her really good