NEW YORK CITY — The ultimate free-spirit Pippi Longstocking pushed off the list by that martinet Mary Poppins! I cannot believe it. My red-pigtailed childhood alter-ego who lived in that crazy house with her horse and monkey unfettered by supervision failed to make the final cut. Exhibition curator Chris Loker shared the clash of “Mary versus Pippi” to illustrate the difficult decisionmaking required to arrive at the Grolier Club’s “One Hundred Books Famous in Children’s Literature,” on view through February 7 at the headquarters of America’s oldest bibliophile society, founded in 1884.