EHN: Add payoff_profile_array

[oyamad]

Close #7

julia> g = NormalFormGame(randn(3, 2, 2))
3×2 NormalFormGame{2, Float64}

julia> print(g)
3×2 NormalFormGame{2, Float64}:
 [1.00783, -0.217958]  [0.888136, -1.82716]
 [0.759667, 0.945713]  [0.217776, -0.718575]
 [-0.224237, 0.42577]  [-0.338728, 0.679999]
julia> g.players[1]
3×2 Player{2, Float64}:
  1.00783    0.888136
  0.759667   0.217776
 -0.224237  -0.338728

julia> g.players[2]
2×3 Player{2, Float64}:
 -0.217958   0.945713  0.42577
 -1.82716   -0.718575  0.679999