Use GetAllHistories in count_all_states example

[jhtschultz]

Updates count_all_states example to use GetAllHistories.

@lanctot this should address the issues raised in your last comment in #402.

It handles both perfect and imperfect information games. Tic tac toe is now included, and we get the correct number of total states: 4520 nonterminal + 958 terminal = 5478 total. The outputs for the other games agree with the current version of the file.

Game: tic_tac_toe, num_histories: 549946, num_terminal_histories: 255168, num_chance_nodes: 0, num_nonterminal_states: 4520, num_terminal_states: 958
Game: kuhn_poker, num_histories: 58, num_terminal_histories: 30, num_chance_nodes: 4, num_nonterminal_states: 12, num_terminal_states: 30
Game: leduc_poker, num_histories: 9457, num_terminal_histories: 5520, num_chance_nodes: 157, num_nonterminal_states: 936, num_terminal_states: 5520
Game: liars_dice, num_histories: 294883, num_terminal_histories: 147420, num_chance_nodes: 7, num_nonterminal_states: 24576, num_terminal_states: 147420
Game: turn_based_simultaneous_game(game=goofspiel(imp_info=true,num_cards=4,players=2,points_order=descending,returns_type=win_loss)), num_histories: 1077, num_terminal_histories: 576, num_chance_nodes: 0, num_nonterminal_states: 162, num_terminal_states: 576
Game: turn_based_simultaneous_game(game=goofspiel(imp_info=true,num_cards=5,players=2,points_order=descending,returns_type=win_loss)), num_histories: 26931, num_terminal_histories: 14400, num_chance_nodes: 0, num_nonterminal_states: 2124, num_terminal_states: 14400
Game: turn_based_simultaneous_game(game=goofspiel(imp_info=true,num_cards=6,players=2,points_order=descending,returns_type=win_loss)), num_histories: 969523, num_terminal_histories: 518400, num_chance_nodes: 0, num_nonterminal_states: 34482, num_terminal_states: 518400

[lanctot]

Perfect, looks good! Thanks @jhtschultz