Risk and performance attribution

New features

• Previously, pyfolio has required a benchmark, usually the U.S. market
  returns SPY. In order to provide support for international equities and
  alternative data sets, pyfolio is now completely independent of benchmarks.
  If a benchmark is passed, all benchmark-related analyses will be performed;
  if not, they will simply be skipped. By George Ho
• Performance attribution tearsheet PR441, PR433, PR442. By Vikram Narayan.
• Improved implementation of get_turnover PR332. By Gus Gordon.
• Users can now pass in extra rows (as a dict or OrderedDict) to display in the perf_stats table PR445. By Gus Gordon.

Maintenance

• Many features have been more extensively troubleshooted, maintained and
  tested. By Ana Ruelas and Vikram
  Narayan.
• Various fixes to support pandas versions >= 0.18.1 PR443. By Andrew Daniels.