COMINGS AND GOINGS>>?Roger Dubuis, the Geneva-based watchmaker, has named Jorge ­Puentes brand president of Roger Dubuis North America and Mexico.Tristan Boyer de Bouillane>>?Tristan Boyer de Bouillane has been named general manager at Swiss watch brand Perrelet. He was the Asia Pacific sales director for Breitling.>>?Lugano Diamonds in Newport Beach, Calif., has named Tami Cook its chief financial officer.>>?Signet Jewelers promoted Lynn Ahlers to the new role of vice president of total rewards, and Jody Wolf to vice president of business support services.>>?The Doneger Group has named Roberto Ramos senior vice president of global strategy and communications. Ramos is the cofounder of creative agency Vox Collective.>>?Steven P. Murphy left his position as CEO of Christie’s at the end of December. Current chairman Patricia Barbizet will take over as