add CSF columns to _confounds.tsv - close #702
add CSF columns to _confounds.tsv - close #702

poldracklab/preprocessing-workflow,oesteban/preprocessing-workflow,oesteban/fmriprep,poldracklab/preprocessing-workflow,poldracklab/fmriprep,oesteban/fmriprep,oesteban/fmriprep,poldracklab/fmriprep,poldracklab/fmriprep,oesteban/preprocessing-workflow