(enh) (#1618) map metadata into dictionary
(enh) (#1618) map metadata into dictionary

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