[3] Kirsten Dunst, Lizzy Caplan, Isla Fisher, and Rebel Wilson headline this flick written and directed by Leslye Headland (based on her stage play). It’s about three self-absorbed young women who somewhat reluctantly agree to be bride’s maids for a mutual acquaintance. Bachelorette is supposed to be a comedy, but it’s so darned mean-spirited and ugly, I had a hard time mustering any laughs. Am …