Weights in Golub-Welsch

Compute the quadrature weights by full Golub-Welsch algorithm.

Reason: for large n the explicit formula for computing the weights will fail due to the division by a polynomial of high degree.


> And this probably should be added to `he_roots` too.

Sure. It is a principal issues. Laguerre and Hermite
polynomials are affected (at least) because they get
evaluated on arbitrary large x values.