Fix pivoting of strategic game tables

[tturocy]

This corrects pivoting of strategic game tables. Specifically, this fixes the resizing of the row and column label panels so they display all of the levels of the index.

Along the way, some internal refactoring is done to separate the local storage of the pivoted view from the user-display wxWidgets level.

[edwardchalstrey1]

Hi @tturocy here is a screenshot from having built the GUI from this branch and opening a game in strategic form view - does this show the row and column labels looking the way you expect?

[tturocy]

@edwardchalstrey1 Try dragging player2 to be on the row labels and see what happens (what you're showing was the case that already worked before)

[edwardchalstrey1]

@edwardchalstrey1 Try dragging player2 to be on the row labels and see what happens (what you're showing was the case that already worked before)

[tturocy]

@edwardchalstrey1 Try dragging player2 to be on the row labels and see what happens (what you're showing was the case that already worked before)

Yeah, that's not good, does not seem to be sizing correctly.