title: Overlay below tiles in Leaflet.js
body: <p>I have a Leaflet.js map, with a base tile layer, a label tile layer, and some overlays. I need to put the label tile layer ABOVE the overlays. I tried bringing it to front using <code>bringToFront()</code> - for no avail.
  Here's the code:</p>
  
  <pre><code>map.addLayer( new L.StamenTileLayer("toner-lines") );
  ...// more code, loading the overlays, etc
  var labels = L.tileLayer('http://{s}.www.toolserver.org/tiles/osm-labels-en/{z}/{x}/{y}.png', {
      maxZoom: 17,
      zIndex: 1000
  });
  labels.addTo(map);
  labels.bringToFront();
  </code></pre>