feat: adde letters, test word only

android/src/com/wordbattle/game/AndroidInterfaceClass.java

...rc/com/wordbattle/game/controller/GamePlayController.java

core/src/com/wordbattle/game/controller/LobbyController.java

...com/wordbattle/game/controller/WaitForHostController.java

core/src/com/wordbattle/game/model/LetterPool.java

core/src/com/wordbattle/game/model/LobbyModel.java

core/src/com/wordbattle/game/network/FirebaseInterface.java

core/src/com/wordbattle/game/network/FirebaseManager.java

core/src/com/wordbattle/game/states/GamePlayState.java

core/src/com/wordbattle/game/view/GamePlayView.java

core/src/com/wordbattle/game/view/GameView.java

core/src/com/wordbattle/game/view/LobbyView.java