On Mother’s Day, family TV shows are especially welcome – and one thing you can say about American Idol, in all its incarnations, is that it’s a show that can be watched by the entire family. So here it is, live, a two-hour competition featuring the new ABC program’s first Top 5 – and with Katy Perry invariably grabbing the biggest share of the spotlight, from contestants and judges alike, as she did on "Disney music" night last week, by dressing as Snow White...