Remove "dominated actions" method

[tturocy]

See #612.

Done so far:

• Remove toolbar from extensive game window in GUI
• Remove computation of "dominated" actions in behavior support profiles, and the associated supporting code that was used only for this.

Still to do:

• Review the documentation for the GUI to remove discussion of dominated actions. This is slightly nontrivial because that discussion comes before that for strategies, so it requires editing not just deletion. Also, the example for dominated strategies is not very interesting (prisoner's dilemma); it would be good to have a larger game which is less trivial (something dominance solvable in a few steps)? A challenge here is the screenshots are fully 15 years old so making a new example would open that can of worms....
• Remove support for "root reachability" in tree layout. This will simplify the layout implementation substantially. It is again something we might someday like to have, but it would be better to re-implement it in a better way from scratch.

[rahulsavani]

The removal of the Dominance toolbar for an extensive game seems to have been done fine, though investigating this did lead to issue #648.

I do note that now when we have an extensive game and click on Dominance under the Tools menu item, nothing happens, which is not ideal, but since this does cause something to happen when viewing the reduced strategic form of an extensive game, and we probably can't make this context specific, we probably just need to have it always appear in the Tools menu.

[tturocy]

The issue of the menu did occur to me. What would you suggest for the behaviour? It should be disabled menu item when viewing the tree? Should it retain its checkbox though? What I mean is: suppose you pass to strategic form, show the dominance toolbar, then go back to extensive. Would Dominance be disabled but still checked? Or would it be disabled and unchecked? And if you then further go back to strategic form, does it return to being active and checked?

[edwardchalstrey1]

I built the GUI from this branch, loaded an EFG and tried Tools -> Dominance and nothing happens, so I agree with Rahul's comments.

@tturocy There is a checkbox in the top comment about updating docs, however I don't see any docs changes in this PR?

[rahulsavani]

The issue of the menu did occur to me. What would you suggest for the behaviour?

1. I think it is nice for it to be disabled when one cannot see the effect of changing it, i.e., whenever one is on the extensive view.
2. Having it checked but disabled in the extensive view can sensibly reflect that when one goes to the strategic view, the dominance stuff will be shown. By 1. though, we then cannot turn it on or off in the extensive view.

So then:

It should be disabled menu item when viewing the tree? Should it retain its checkbox though?

I think it should retain the check box, but it can't be changed from the extensive view.

What I mean is: suppose you pass to strategic form, show the dominance toolbar, then go back to extensive. Would Dominance be disabled but still checked?

Yes.