When Mark Clements came to Milwaukee to be artistic director of the Rep, he brought musicals, a charming British accent and Aaron Posner. A writer and director, Posner was responsible for the Rep's stunning production of "My Name is Asher Lev" in the Stiemke Theater in the fall of 2010. It was the high point of Clements' impressive inaugural season. Now Posner is back at the Rep to direct "To Kill a Mockingbird."