enh: add flag for cleaning working directories
enh: add flag for cleaning working directories

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