[Bug-gnubg] Feature request - Indicate who is on roll

[Ian Shaw]

I would find it very helpful to have an indicator at the side of the board to 
show who is on roll. I'm surprised at how often I end up confused! Not so much 
during actual play, but whilst playing around with positions.
I would like to see an arrow, like Snowie and Jellyfish, or maybe go one-up by 
having a picture of a dice cup ;)
--Ian