The death of KMET in Los Angeles was a turning point in my young father's life. I was 6 years old when it signed off permanently, ending commercial viability of the progressive, freeform rock format on L.A.'s FM dial. It's also one of my earliest memories: Windows down and heater up on a cloudy February morning, sitting backseat in an Arby's parking lot before kindergarten, the sound of heresy on