You might know Rose Byrne as a condescending bridesmaid, or as a dramatic actor going toe-to-toe with Glenn Close, or maybe as half of a Hollywood power couple with actor Bobby Cannavale. But now, in "If I Had Legs I'd Kick You," Rose Byrne is just a woman at the end of her rope. Her character's life is a smorgasbord of disaster: a working mom with a demanding job, with a very sick kid, who's been forced to live in a motel after a plumbing disaster ruined their house. Not even her therapist (