Add unit tests to zombie_dice

[a-temlyakov]

Currently there are almost no unit tests:

go test ./... -cover
? github.com/Akavall/GoGamesProject [no test files]
ok github.com/Akavall/GoGamesProject/dice 0.028s coverage: 96.6% of statements
? github.com/Akavall/GoGamesProject/dice_war [no test files]
ok github.com/Akavall/GoGamesProject/statistics 0.009s coverage: 100.0% of statements
ok github.com/Akavall/GoGamesProject/zombie_dice 0.177s coverage: 19.6% of statements

go tool cover -func=coverage.out
github.com/Akavall/GoGamesProject/zombie_dice/ai.go:8: GreedyAI 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/ai.go:15: CarefulAI 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/ai.go:22: RandomAI 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/ai.go:27: SimulationistAI 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/ai.go:56: simulate_one_roll 100.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_deck.go:11: Shuffle 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_deck.go:15: DealDice 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_deck.go:19: AddDice 100.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_deck.go:23: InitZombieDeck 100.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_deck.go:55: make_slice_of_sides 100.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_dice.go:48: EndTurn 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_dice.go:63: endRound 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_dice.go:81: Reset 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_dice.go:88: InitGameState 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_dice.go:95: TakeTurn 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_dice.go:136: InitPlayerState 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_dice.go:140: shouldKeepGoing 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_dice.go:172: PlayWithAI 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_dice.go:231: get_terminal_input 0.0%
github.com/Akavall/GoGamesProject/zombie_dice/zombie_dice.go:239: select_ai 0.0%
total: (statements) 19.6%