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tokens: We thank the anonymous referee for very useful comments and suggestions that substantially improved the manuscript. We are also grateful to M. Kromer for useful discussions about theoretic progenitor scenarios and to A. De Cia, O. Yaron, D. Tal, D. Perley, K. Tinyanont, A. Waszczak, I. Arcavi, and S. Tang for performing observation and data reduction. This research is partly supported by the Swift Guest Investigator program and by the National Science Foundation. Y.C. and M.M.K. acknowledge support from the National Science Foundation PIRE program grant 1545949. A.G. and R.A. acknowledge support from the Swedish Research Council and the Swedish Space Board. E.Y.H. acknowledges the support provided by the Danish Agency for Science and Technology and Innovation through a Sapere Aude Level 2 grant. Some observations were obtained with the SuperNova Integral Field Spectrograph on the University of Hawaii 2.2 m telescope as part of the Nearby Supernova Factory II project, a scientific collaboration between the Centre de Recherche Astronomique de Lyon, Institut de Physique Nucl’eaire de Lyon, Laboratoire de Physique Nucl’eaire et des Hautes Energies, Lawrence Berkeley National Laboratory, Yale University, University of Bonn, Max Planck Institute for Astrophysics, Tsinghua Center for Astrophysics, and Centre de Physique des Particules de Marseille. Some data in this paper were obtained with ALFOSC, which is provided by the Instituto de Astrofisica de Andalucia (IAA) under a joint agreement with the University of Copenhagen and NOTSA. We also thank the RATIR project team and the staff of the Observatorio Astronómico Nacional on Sierra San Pedro Mártir. RATIR is a collaboration between the University of California, the Universidad Nacional Autónoma de México, NASA Goddard Space Flight Center, and Arizona State University, benefiting from the loan of an H2RG detector and hardware and software support from Teledyne Scientific and Imaging. RATIR, the automation of the Harold L. Johnson Telescope of the Observatorio Astronómico Nacional on Sierra San Pedro Mártir and the operation of both is funded through NASA grants NNX09AH71G, NNX09AT02G, NNX10AI27G, and NNX12AE66G, CONACyT grants LN 260369, and UNAM PAPIIT grant IG100414. A portion of this work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. Copyright 2016 California Institute of Technology. All Rights Reserved. US Government Support Acknowledged.