add handling for gzipped nifti
add handling for gzipped nifti

cerr/CERR,cerr/CERR,aditiiyer/CERR,cerr/CERR,aditiiyer/CERR,aditiiyer/CERR,cerr/CERR,cerr/CERR,aditiiyer/CERR,aditiiyer/CERR,cerr/CERR,cerr/CERR,aditiiyer/CERR,aditiiyer/CERR,cerr/CERR,aditiiyer/CERR,cerr/CERR