title: ui-gmap-markers is not working
body: <p>im trying to put some markers in a map using the angular-google-maps library, i can draw <strong>one</strong> marker using <code>ui-gmap-marker</code> but not <strong>many</strong> markers using <code>ui-gmap-markers</code>. Here is my <strong>js</strong> code.</p>
  
  <pre><code>angular.module('myApp').controller('homeController', [homeController]);
  
  function homeController(){
      var vm = this;
  
      vm.map = {
          center:{
              latitude: 46.8032826,
              longitude: -71.242796
          },
          zoom: 12
      };
  
      vm.places = [
                   {
                     idKey: 583187,
                     latitude: 46.7682,
                     longitude: -71.3234,
                     title: "title"
                   }
                 ];
  };
  </code></pre>
  
  <p>the <strong>html</strong> :</p>
  
  <pre><code>&lt;ion-view ng-controller="homeController as vm"&gt;
  &lt;ui-gmap-google-map draggable="true" center="vm.map.center" zoom="vm.map.zoom"&gt;
      &lt;ui-gmap-markers models="vm.places" coords="'self'" icon="'icon'"&gt;&lt;/ui-gmap-markers&gt;
  &lt;/ui-gmap-google-map&gt;
  &lt;/ion-view&gt;
  </code></pre>
  
  <p>I can see the map, with a <code>console.log</code> i can see that the <code>places</code> array is correctly set, but i see no markers at all ! what is wrong with my code ?</p>
  
  <p>Thank you.</p>
  
  <p>PS: notice im using ionic, im sur it has nothing to do with the problem.</p>