Update matrix_exponential test after API change in ei_matrix_function Apologies for forgetting this yesterday and not testing properly.
Update matrix_exponential test after API change in ei_matrix_function
Apologies for forgetting this yesterday and not testing properly.

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