“Family Guy” celebrates its 100th episode on Sunday (9 p.m.) Pretty sweet for a show that was canceled, not once, but twice. “Family Guy” has survived every roadblock to become an animated classic. Episode 100 is titled “Stewie Kills Lois.” Should be fun. Lois and Peter go on a cruise, leaving Stewie and the family behind. When Stewie gets upset with Lois for leaving him at home, he vows to carry out a diabolical plan. When Brian challenges him to actually do it, Stewie stows away on the ship, finds Lois and… someone dies. We’re betting it won’t be Lois. Fox will lead into the milestone episode with a tribute special at 8:30 p.m.