SERIES FINALE: When this series began in 2012, Lena Dunham’s Hannah, an aspiring writer, declared herself to her parents as “the voice of her generation,” then walked it back a bit to amend it as, maybe, “a voice of a generation.” Dunham and girls started as the latter, and has successfully become the former. Last week, it stuck its four primary women characters in a bathroom for what may or may not have been their last group argument. Tonight, Girls presents its finale – the TV event of the night.