L.A Times: A young mother who allegedly shot her two boys Saturday -- killing her 5-year-old and critically wounding her 1 1/2 -year-old -- shouted, "I've wasted my life!" from her balcony and threatened to kill herself before she was arrested, police and neighbors said. LaTonya Dixon, 25, called 911 about 8:30 a.m. Saturday and told the dispatcher that she had killed her children. When officers arrived at the three-unit apartment complex in the 7200 block of South Gra…