title: ng-table filterData does not work
body: <p>Please help to point the problem in my code bellow: why the drop down select items are not shown. I went through the <a href="http://ng-table.com/#/filtering/demo-select" rel="nofollow noreferrer">ngTable Example</a> it did not give me all the details. I cannot find the source <code>ngTableDemos</code> so I have no idea what the <code>filterData</code> should exactly be and it is made by my guess.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>      "use strict";
        angular.module('myApp', ['ngTable']).controller("myCtrl", ['NgTableParams', function (NgTableParams) {
          this.cols = [
            {field: 'name', title: 'Name', filter: {name: 'text'}},
            {field: 'age', title: 'Age', filter: {age: 'number'}},
            {field: 'gender', title: 'Gender', filter: {gender: 'select'}, filterData: ['male', 'female', 'shemale']}
          ];
          this.tbParams = new NgTableParams({}, {
            dataset: [
              {name:'abc1001',age:11,gender:'male'},
              {name:'abc1002',age:12,gender:'female'},
              {name:'abc1003',age:13,gender:'shemale'}
            ]
          });
        }]);</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!DOCTYPE html&gt;
  &lt;html ng-app="myApp"&gt;
    &lt;head lang="en"&gt;
      &lt;title&gt;demo23&lt;/title&gt;
      &lt;meta charset="utf-8"&gt;
      &lt;script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.6.6/angular.js"&gt;&lt;/script&gt;
      &lt;script type="text/javascript" src="https://unpkg.com/ng-table@4.0.0/bundles/ng-table.min.js"&gt;&lt;/script&gt;
      &lt;link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" /&gt;
      &lt;link rel="stylesheet" href="https://unpkg.com/ng-table@4.0.0/bundles/ng-table.min.css" /&gt;
    &lt;/head&gt;
    &lt;body&gt;
      &lt;div class="container-fluid" ng-controller = "myCtrl as ctrl"&gt;
        &lt;table ng-table-dynamic="ctrl.tbParams with ctrl.cols" class="table table-condensed table-bordered table-striped"&gt;
          &lt;tr ng-repeat="row in $data"&gt;
            &lt;td ng-repeat="col in $columns" &gt;{{row[col.field]}}&lt;/td&gt;
          &lt;/tr&gt;
        &lt;/table&gt;
      &lt;/div&gt;
    &lt;/body&gt;
  &lt;/html&gt;</code></pre>
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  </div>
  </p>