The Florida Highway Patrol says a 7-year-old girl from Tallahassee was killed Sunday in a traffic crash on Interstate 10 in Jackson County after the car she was traveling in rear-ended a mini-van. Troopers say 34-year-old Heather Foster, also of Tallahassee, was eastbound on I-10 at about 7:50 p.m. when she collided with a vehicle driven by 69-year-old Calvin Odom, of Middleburg, Florida, which had slowed for traffic.   Foster and Odom suffered minor injuries, but 7-year-old Liliana Clanton, was killed. All parties were wearing their seatbelts and alcohol was not a factor.