At Wit's End"America's irrepressible doyenne of domestic satire."THE BOSTON GLOBEMadcap, bittersweet humor in classic Erma Bombeck style. You'll laugh until it hurts and love it! "Any mother with half a skull knows that when Daddy's little boy becomes Mommy's little boy, the kid is so wet, he's treading water. What do you mean you're a participle in the school play and you need a costume? Those rotten kids. If only they'd let me wake up in my own way. Why do they