Speaking of Nixon, as Mojo Nixon once sang, “Elvis, Elvis, Elvis, Elvis, Elvis, Elvis.” Although aliens abducted him all the way back in ’77, The King is still very much with us with more tributes on stage, screen and the airwaves than most of us have karate kicks. Laying out the royal treatment in a big way are 20 bands gathering at Local 506 (and next door at the Sportsbar) for the annual Elvisfest Friday and Saturday, Jan. 7-8