Fix ordering of Gauss Hermite weights

Hi Alex,

This should fix the issues that would otherwise arise when:

    using FastGaussQuadrature
    f(x) = 1+x.^2;
    for n in [0 1 20 200 201 202]
          x,w = gausshermite(n);
          println(dot(f(x),w))
    end

Mikael