A heartless Arkansas day care owner was charged with capital murder after she allegedly snapped and slammed an infant’s head into the floor multiple times while changing his diaper, police said. Erin Sauls, 23, was arrested Tuesday after fatally bashing the 8-month-old boy’s head into the hardwood floor three times at her Little Rock home day care when she developed a “headache” and became “frustrated” during a diaper change, according to charging documents obtained by…