Fix a  nasty index-out-of-bounds bug
Fix a  nasty index-out-of-bounds bug

The zeroth quantile of the normal distribution is defined to be
-infinity, leading to a huge negative vector index being generated
if none of the resampled values are less than the sample mean.

This fixes bos/criterion#52.

Shimuuar/statistics,bos/statistics,mihaimaruseac/statistics,Shimuuar/statistics,fpco/statistics,mihaimaruseac/statistics,mihaimaruseac/statistics,fpco/statistics,bos/statistics