BUGS:

TODO:
    - update game viewport on zoom
    - german promotion sound
    - tutorial
        - moves
        - HQ moves
        - objectives
        - engagement
    - pause / resume
    - maybe do not need cancel button in engagement and HQ mode, but must support canCancel option
    - desktop config :
        - config.fullscreen = false;
        - config.forceExit = true;
        - config.vSyncEnabled = true;

NEXT:
    - support different board layout
        - north orientation
        - hex orientation
        - inverted even/odd row scheme
    - automatic overlays to show unit stack depth


RESOURCES
    - better to track installation:
        - http://android-developers.blogspot.ch/2011/03/identifying-app-installations.html

    - integrate native android stuff in libgdx:
        - https://code.google.com/p/libgdx-users/wiki/IntegratingAndroidNativeUiElements

    - crypt:
        - https://code.google.com/p/gwt-crypto/

    - font:
        - http://kvazars.com/littera/

    - device unique ID:
        final TelephonyManager tm = (TelephonyManager) getBaseContext().getSystemService(Context.TELEPHONY_SERVICE);

        final String tmDevice, tmSerial, androidId;
        tmDevice = "" + tm.getDeviceId();
        tmSerial = "" + tm.getSimSerialNumber();
        androidId = "" + android.provider.Settings.Secure.getString(getContentResolver(), android.provider.Settings.Secure.ANDROID_ID);

        UUID deviceUuid = new UUID(androidId.hashCode(), ((long)tmDevice.hashCode() << 32) | tmSerial.hashCode());
        String deviceId = deviceUuid.toString();