Merge branch '29-join-lobby-backend' into 'main'

android/build.gradle

android/proguard-rules.pro

android/project.properties

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

assets/WaitingForPlayersToFinish.png

assets/uiSkin.json

assets/uiskin.atlas

assets/uiskin.png

build.gradle

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

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

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

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

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

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

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