title: Angular Smart table filter state save dropdown doesn't restore properly
body: <p>I have followed the instructions in the documentation regarding persisting the filter state. (<a href="http://plnkr.co/edit/ekwiNt?p=preview" rel="nofollow">http://plnkr.co/edit/ekwiNt?p=preview</a>) </p>
  
  <p>When re-loading the page, the table state (including filters) is restored, however the <code>&lt;select&gt;</code> box appears blank, even though the filter does work.</p>
  
  <p>The text filter works fine.</p>
  
  <p>Angular 1.4.7
  Smart-table 2.1.5</p>
  
  <p>Here is the plunker
  <a href="https://embed.plnkr.co/fK6WfZSZrgSeIG732R2X/" rel="nofollow">https://embed.plnkr.co/fK6WfZSZrgSeIG732R2X/</a></p>
  
  <pre><code>.directive('stPersist', function() {
    return {
      require: '^stTable',
      link: function(scope, element, attr, ctrl) {
        var nameSpace = attr.stPersist;
  
        //save the table state every time it changes
        scope.$watch(function() {
          return ctrl.tableState();
        }, function(newValue, oldValue) {
          if (newValue !== oldValue) {
            localStorage.setItem(nameSpace, JSON.stringify(newValue));
          }
        }, true);
  
        //fetch the table state when the directive is loaded
        if (localStorage.getItem(nameSpace)) {
          var savedState = JSON.parse(localStorage.getItem(nameSpace));
          var tableState = ctrl.tableState();
  
          angular.extend(tableState, savedState);
          ctrl.pipe();
  
        }
  
      }
    };
  });;
  </code></pre>