Acknowledgements
We would like to thank Emanuele Berti, Vitor Cardoso, William Nelson, Bangalore Sathyaprakash, and Leo Stein for many discussions. We would also like to thank Laura Sampson and Tyson Littenberg for helping us write parts of the data analysis sections. Finally, we would like to thank Matt Adams, Katerina Chatziioannou, Tyson Littenberg, Laura Sampson, and Kent Yagi for proof-reading earlier versions of this manuscript. Nicolás Yunes would like to acknowledge support from NSF grant PHY-1114374 and NASA grant NNX11AI49G, under sub-award 00001944. Xavier Siemens would like to acknowledge support from the NSF CAREER award number 0955929, the PIRE award number 0968126, and award number 0970074.