1. Canadian Institute for Theoretical Astrophysics, 60 St George Street, University of Toronto, ON M5S 3H8, Canada
2. Department of Physics, Institute for Computational Cosmology, Durham University, South Road, Durham DH1 3LE, UK
3. Canadian Research Chair in Theoretical Astrophysics, Queen's University Kingston, ON K7L 3N6, Canada
4. Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University, CIERA, Evanston, IL 60201, USA
5. Department of Physics and Astronomy, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208, USA
6. TAPIR, MC 350-17, California Institute of Technology, Pasadena, CA 91125, USA
7. Department of Physics, University of California, Davis, CA 95616, USA
8. Department of Physics, Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla, CA 92093, USA
9. Institute for Computational Science, University of Zurich, Zurich CH-8057, Switzerland