add another Nist test of 'hard' difficutly : Bennett5
add another Nist test of 'hard' difficutly : Bennett5

madlib/eigen_backup,rotorliu/eigen,mjbshaw/Eigen,mjbshaw/Eigen,madlib/eigen_backup,mjbshaw/Eigen,mjbshaw/Eigen,madlib/eigen_backup,rotorliu/eigen,rotorliu/eigen,madlib/eigen_backup,rotorliu/eigen