Competing in the International Federation of Sleddog Sports Winter Worl Championships last month, Ipswich High sophomore Lily Stewart and her four dogs — Grinder, Chess, KT, and Endo — went toe-to-toe with the world’s best female mushers in a free-for-all that had all the makings of a canine-powered demolition derby over a slick 5.7-mile course.Read and see photos here: http://www.boston.com/yourtown/ipswich-teen-and-sled-dogs-win-big/2tncIJVNulLabk1yqKGjIO/gallery.html