AvatarJean Viauflipped into PicksAvatarAvatarContador banks on team work to challenge Skyverified_publisherReutersMADRID (Reuters) - Spanish cyclist Alberto Contador is targeting a third Tour de France victory in 2017 with his new American team Trek-Segafredo and believes Team Sky will again provide the biggest challenge. The 33-year-old, winner of the sport's most prestigious race in 2007 and 2009, will ride …