[Major Upgrade] Impartial Leader Selector

[rerathbun]

Actually, the leader lists have already been made. 


On the pages where you enter the leaders for the scenario, "Define Draw Pools"  is a reminder to use the window on the right to tell the selector which game the leaders are drawn from.  It's necessary even when defining scenarios from boxed games where the leaders are all from that game.  If you don't tell the selector where to look for the leaders, it gets confused and messes up the leader selection.