title: MarkerWithLabel label center alignment
body: <p>I'm using the MarkerWithLabel extension in Google Maps API v3. I would like to set the label below the picture to be center aligned.
  There is an LabelAnchor property that sets the position of the label, and I also use an CSS labelClass like this:</p>
  
  <pre><code>var myMarker = new MarkerWithLabel(
  {
      position: latlng,
      draggable: false,
      raiseOnDrag: false,
      map: map,
      labelContent: "my text",
      labelAnchor: new google.maps.Point(25, 0), //(25, 27),
      labelClass: "my_label", // the CSS class for the label
      labelStyle: {opacity: 0.8},
      icon: image,
      labelInBackground: true,
      labelVisible: true,
      clickable: true,
      zIndex: 11
  });
  
  .my_label 
  {
      color: black;
      background-color: beige;
      font-family: "Lucida Grande", "Arial", sans-serif;
      font-size: 10px;
      text-align: center;
      width: auto;     
      white-space: nowrap;
      padding: 4px;
      border: 1px solid grey;
      border-radius:3px;   
      box-shadow: 2px 2px 20px #888888;
  }
  </code></pre>
  
  <p>Is it possible to auto align the label box, or do I need to calculate the text width and set the LabelAnchor manually? And if so, how do I calculate the text width?</p>