1. Institute for Computational Science, University of Zürich , Winterthurerstrasse 190, 8057 Zürich, Switzerland
2. Department of Physics & Astronomy, University of California , Davis, CA 95616, USA
3. California Institute of Technology , TAPIR, Mailcode 350-17, Pasadena, CA 91125, USA
4. CIERA and Department of Physics and Astronomy, Northwestern University , 1800 Sherman Ave, Evanston, IL 60201, USA