AndroidSystem delegate doesn't check for null audio renderers

[riccardobl]

The AndroidSystem doesn't seem to have a way to allow to disable the audio renderer, see code below:

jmonkeyengine/jme3-android/src/main/java/com/jme3/system/android/JmeAndroidSystem.java

Lines 79 to 86 in 09b862d

	if (settings.getAudioRenderer().equals(AppSettings.ANDROID_MEDIAPLAYER)) {
	audioRendererType = AppSettings.ANDROID_MEDIAPLAYER;
	} else if (settings.getAudioRenderer().equals(AppSettings.ANDROID_OPENAL_SOFT)) {
	audioRendererType = AppSettings.ANDROID_OPENAL_SOFT;
	} else {
	logger.log(Level.INFO, "AudioRenderer not set. Defaulting to OpenAL Soft");
	audioRendererType = AppSettings.ANDROID_OPENAL_SOFT;
	}

Setting audio renderer to null, as you would do with desktop, causes the engine to crash, due to the missing nullcheck.

[stephengold]

Thanks for documenting this issue, @riccardobl .