[Catalog]/[Tutorial]: Geometry of Nash and correlated equilibria

[tturocy]

This paper has some nice examples and visualisations of the geometry of Nash equilibria and correlated equilibria:

Nau, Robert, Gomez Canovas, Sabrina, and Hansen, Pierre (2004). On the geometry of Nash equilibria and correlated equilibria. International Journal of Game Theory 32(4): 443-453.

We should:

1. Add the several games from this paper to the catalog. (One already exists as contrib/games/2x2x2-nau.nfg).
2. Add a tutorial/example notebook which replicates the visualisations in the paper.