Implement random player order selection.

[furadnik]

No description provided.

[MARTESING]

We discussed it with David today and realised we can use rm_step instead of rm_step_plus and it chooses the order randomly enough.

Also, we had to increase the number of iterations to not get nash_conv "alerts". For some of the parameters, I get nash_conv alert even for 5 000 iterations, though (like 3 out of 90 sets of parameters).