Fix state-weighting

[gramian]

The state weighting closure (emgr.m, line 180) should be:

            wei = @(m) 1.0 ./ max(sqrt(eps),vecnorm(m,2,1));

similarly emgr.py, line 212 should be:

            return 1.0 / np.maximum(math.sqrt(np.spacing(1)),np.linalg.norm(m, 2, axis=0))

This will be fixed in version 5.9