The parents of accused Chico library shooter Bradley Sayer fought over his access to guns during their bitter divorce battle, the California Post can reveal. The 18-year-old, said to be a “fan” of the infamous Columbine High School massacre , is accused of fatally shooting two men, Jacob “Cody” Hull, 46, and Robert Johnson, 74, during the June 22 attack. Court documents exclusively obtained by The Post lay bare how Sayer’s mother, Vicki Sayer, 51, was against her autistic son being permitted to