improve accuracy of 3x3 direct eigenvector extraction
improve accuracy of 3x3 direct eigenvector extraction

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