* dlae2.f  has better handling of 2x2 eigenvalues than our qrstep.c* Document Jacobi eigen function, in particular that it only works forsymmetric matrices.* add support for nonsymmv left eigenvectors?:  gsl_eigen_nonsymmv_params(const int lr)  to specify whether we should compute left/right eigenvectors (or both).  If they want both, we'll need a new function:  gsl_eigen_nonsymmv_lr(..., evec_r, evec_l, ...)  and  gsl_eigen_nonsymmv_lr_Z(...)