afni_proc_simple_bids_app

First draft of making an afni_proc.py BIDS-App with "simple" afni_proc.py processing (for single echo FMRI at the moment)

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To run (see details in program help file):

Execute the scripts/run_ap_simple_bidsapp script with 2 args:

 DIR_INPUT  : BIDS-formatted input directory
 DIR_OUTPUT : to-be-created output directory of processed sets

Example:

 scripts/run_ap_simple_bidsapp bids_dataset afni_proc_dataset