A review article, submitted to Annual Reviews of Astronomy and Astrophysics, and available for download.
All content is Copyright 2014 by the authors:
If you would like to comment on the review, please submit an issue to this repository at this link. We may be able to make small changes during the refereeing process; otherwise, feel free to simply add your feedback so that everyone (including any subsequent reviewers) can see it. Thanks very much!
You can also view the review in its own personal online webpage, built by gh-publisher by Ewan Mellor. The PDF visible here (and at the download link above) is automatically built at Travis CI.