Zero-dimensional arrays should be accepted as scalars

[burnpanck]

Currently, zero-dimensional arrays get rejected on NumericalTrait(ndim=0), as the latter requires the value to be np.isscalar. Unfortunately np.isscalar(np.array(1)) == False. The error is particularly annoying in conjunction with quantities, as quantities.Quantity is a subclass of np.ndarray and thus it's instances are not numpy array scalars.

[astrofrog]

I agree, it would be nice for this to work. Would you be interested in contributing a patch?

[burnpanck]

I have to admit that the validation code looks quite complicated to me (does it have to be that complicated?), so I do not want to mess too much with it. I think I have a fix that works though...