title: kml google extensions not in schema
body: <p>The jurisdiction I live in published data using a Google globe.  The kml file they point to contains</p>
  
  <pre><code>&lt;?xml version='1.0' encoding='UTF-8'?&gt;
  &lt;kml xmlns="http://www.opengis.net/kml/2.2"
       xmlns:gx="http://www.google.com/kml/ext/2.2"&gt;
           &lt;gx:GoogleMapsEngineLink&gt;
           &lt;href&gt;http://globe.information.qld.gov.au/qldglobe&lt;/href&gt;
       &lt;/gx:GoogleMapsEngineLink&gt;
  &lt;/kml&gt;
  </code></pre>
  
  <p>I can't find any reference to the gx:GoogleMapsEngineLink in any public documentation and I am having trouble using that with other standard kml, for example a Place.  I'd like a kml that pens this government globe and also adds a Place.  </p>
  
  <p>I'd like to be able to add this Place to the Above kml (ie. one kml file)</p>
  
  <pre><code>&lt;?xml version='1.0' encoding='UTF-8'?&gt;
  &lt;kml xmlns="http://www.opengis.net/kml/2.2"
  &lt;Placemark&gt;
  &lt;description&gt;Some nice place&lt;/description&gt;
  &lt;Point&gt;
  &lt;coordinates&gt;153.0064595002,-27.4811714996,0&lt;/coordinates&gt;
  &lt;/Point&gt;
  &lt;Style&gt;
      &lt;LabelStyle&gt;
       &lt;color&gt;ff7fffff&lt;/color&gt;
      &lt;/LabelStyle&gt;
  &lt;/Style&gt;
  &lt;/Placemark&gt;
  &lt;/kml&gt;
  </code></pre>