Bill Maher didn’t exactly go easy on his pal Al Franken tonight, spending much of the opening monologue and a big chunk of Real Time’s season finale tossing joke grenades at the Minnesota senator. But the HBO host drew a hard line between the former Saturday Night Live staffer and the ever-growing gang of famous abusers and grabbers. Maher then described the scandal – the photo of Franken “mock-groping” Leeann Tweeden, then writing and demanding a rehearsal of a sketch…