Allow bare .nii files instead of .nii.gz
Allow bare .nii files instead of .nii.gz

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