MEDINAH, Ill. (AP) - The question used to come up every other year when the Americans began looking ahead to the Ryder Cup."Who's their Peter Baker?"Europe always had at least one player the Americans didn't know anything about until losing to him. Baker played in only one Ryder Cup, going 3-1 in 1993 and winning a singles match against Corey Pavin, one of the toughest guys to beat in match play.Those days are gone. As golf has expanded its borders, the Ryder Cup no longer has any mystery guests.Eight of the Europeans have joint membership on the PGA Tour, and …