[d-kad]

Description of the changes in this PR

Adds Game.set_strategies(player, strategies, drop=False, add=True), which declares the ordered
list of a player's strategies in a game in strategic form, matching by label. An entry matching a
current label keeps that strategy and the outcomes at its contingencies; an entry matching none
creates a strategy with no outcome at any of its contingencies; a current strategy whose label is
not listed is deleted, along with the outcomes at its contingencies. Listing the current labels in
a new order reorders the strategies, permuting the payoff table to match -- not previously
expressible. Deleting is destructive, so it must be confirmed with drop=True.

Game.add_strategy and Game.delete_strategy are removed, as set_strategies subsumes both.

[tturocy]

Generally looking good. @rahulsavani @d-kad the usual drill - left-clicking on strategies in the normal form GUI now generates a dialog with should operate just like the edit-move dialog does for actions. Seems to work well for me, please put it through its paces!

[d-kad]

Tested Edit strategies dialog on macOS: renaming, reordering, adding, deleting with restore all behave well.

The only problem I spotted: with a new 2x2 strategic game, adding players repeatedly crashes loudly at around the 5th player (screenshot)

[tturocy]

Tested Edit strategies dialog on macOS: renaming, reordering, adding, deleting with restore all behave well.

The only problem I spotted: with a new 2x2 strategic game, adding players repeatedly crashes loudly at around the 5th player (screenshot)

This turned out to be a bug in NewPlayer, completely separate from this. I've patched it for this PR, but actually it should get fixed "automatically" in the set_players changes.