tree edges unnecessarily crossing info sets

[stengel]

This relates to game tree layout. Terminal nodes should be drawn high enough to avoid crossing info sets. The extra third node on the left should be drawn higher up (this is - correctly so - independent of the way the game tree is created, here I added the extra node to player 2's info set afterwards):

whereas GTE does it right:

Also, the MOVE LABELS should be at the same height and not just the middle of the tree edge. Again, correctly in GTE.