add checks for on the right triangular solving with matrices
add checks for on the right triangular solving with matrices

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