Allegedly abusive lefty Maine Senate hopeful Graham Platner wasn’t just rough on his ex-girlfriends and sexting behind his wife’s back — he was also an “a-hole extraordinaire” as a bartender. Platner, who faced a firestorm this week as he tries to unseat longtime Republican Senator Susan Collins and help the Democrats win the Senate majority, was a deeply unpleasant barkeep at Washington DC’s Tune Inn, one regular claimed. “Platner was just kind of dark, you’d try to turn up a little