documents on initialization lacking about leonids

[ynkm169]

i changed it to this and now it is working...

@Override
public void onWindowFocusChanged (boolean hasFocus) {
    ViewGroup button = (ViewGroup) findViewById(R.id.emitterParent);
    for (int i = 0; i < button.getChildCount(); i++) {
        new ParticleSystem(this, 1000, R.drawable.particlestar, 600, R.id.drawingBg)        

        .emit(button.getChildAt(i), 50);
    };
}

[plattysoft]

Yes, it is explained in the response to issue #22 and #21

Maybe it is a good idea to add it to the documentation.