add support for add'l structure masks in LDDMM
add support for add'l structure masks in LDDMM

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