Added TO-DO comment/question in plotting.plot_rolling_returns() for h…

…ow to properly address Issue #152

pyfolio/plotting.py

@@ -600,6 +600,11 @@ def draw_cone(returns, num_stdev, live_start_date, ax):
                          'factor_returns.')
     elif volatility_match and factor_returns is not None:
         bmark_vol = factor_returns.loc[returns.index].std()
+        # TO-DO: @tweicki 'returns' probably needs to get updated to:
+        # (returns / returns.std()) * bmark_vol if we want to plot
+        # the cone on this later on.
+        # Will we need a temp variable to do this? Or can we just re-assign as
+        # returns = (returns / returns.std()) * bmark_vol
         df_cum_rets = timeseries.cum_returns(
             (returns / returns.std()) * bmark_vol,
             1.0