progress bar for data module

[akeshavan]

from dmriprep.data import get_dataset
get_dataset('path/to/output/dir') # needs a progress bar in bash and also on notebook?

• also would be nice if pathlib made the folder for you if it doesn't already exist mkdir -p
• maybe remove Site-SI from output folder structure

[akeshavan]

also for the HBN data, add the function that moves the T1.nii.gz in derivatives to the freesurfer folder.

[richford]

Closed by #38