EPI distortion correction will fail in cases where the imaging axis is rotated

[jchen33344]

Line 180 in designer_input_utils.py is not robust to variations in header information. pe_dir.append(i['PhaseEncodingDirection'])

Suggest to use mrinfo to extract pe_dir instead:

tmp=$(mrconvert dwi.nii.gz -json_import dwi.json - | mrinfo - | grep PhaseEncodingDirection)
pe_dir=${tmp##*: }