thumbnails in utility nodes (to display output)

[RRIS]

So the common way to preview the output of utility nodes is to hit C to show the color output in the scene, but it would be nice if each utility node also had a thumbnail that shows this output by itself.
That way if you have a couple of nodes chained to each other it's quicker to troubleshoot and see where in the chain the issue occurs instead of having to go through each one individually (meaning that if you change for example a contrast setting in the beginning of the chain, the ones following it will update with it).