BF - only use numpy percentile if available
BF - only use numpy percentile if available

It's available for numpy >= 1.5.0

arokem/nipy,bthirion/nipy,alexis-roche/register,alexis-roche/nireg,bthirion/nipy,arokem/nipy,alexis-roche/nipy,nipy/nireg,alexis-roche/register,arokem/nipy,nipy/nipy-labs,bthirion/nipy,alexis-roche/nipy,alexis-roche/niseg,arokem/nipy,alexis-roche/niseg,nipy/nireg,alexis-roche/nipy,alexis-roche/nipy,nipy/nipy-labs,alexis-roche/register,bthirion/nipy,alexis-roche/nireg