title: bootstrap-table-filter-control extension doesn't work in bootstrap-table
body: <p>I use <a href="http://bootstrap-table.wenzhixin.net.cn/" rel="noreferrer">bootstrap-table</a> and would like to use <a href="http://bootstrap-table.wenzhixin.net.cn/extensions/#table-filter-control" rel="noreferrer">table-filter-control</a> extension. In <a href="https://github.com/wenzhixin/bootstrap-table-examples/blob/master/extensions/filter-control.html" rel="noreferrer">this</a> example you can see how to use this extension. When I want to use this extension for more columns, it doesn't work. In my example filter works only for one column.</p>
  
  <p><a href="http://jsfiddle.net/5h595r6g/7/" rel="noreferrer">jsfiddle</a></p>
  
  <p><strong>html</strong></p>
  
  <pre><code>&lt;table ref="mainTable" class="table table-striped table-bordered table-hover" 
         cellSpacing="0" id="mainTable" data-show-toggle="true" 
         data-show-columns="true" data-search="true" data-pagination="true" data-filter-control="true"&gt;
      &lt;thead&gt;
          &lt;tr&gt;
              &lt;th data-field="state" data-checkbox="true"&gt;&lt;/th&gt;
              &lt;th data-field="Customer Name" data-sortable="true" data-filter-control="select"&gt;Customer Name&lt;/th&gt;
              &lt;th data-field="Location Type" data-sortable="true"&gt;Location Type&lt;/th&gt;
              &lt;th data-field="Location" data-sortable="true" data-filter-control="select"&gt;Location&lt;/th&gt;
          &lt;/tr&gt;
      &lt;/thead&gt;
      &lt;tbody&gt;
          &lt;tr&gt;
              &lt;td&gt;&lt;/td&gt;
              &lt;td&gt;Cap Corp&lt;/td&gt;
              &lt;td&gt;Main&lt;/td&gt;
              &lt;td&gt;Norwalk CT 06851&lt;/td&gt;
          &lt;/tr&gt;
          &lt;tr&gt;
              &lt;td&gt;&lt;/td&gt;
              &lt;td&gt;Cap Corp&lt;/td&gt;
              &lt;td&gt;Other&lt;/td&gt;
              &lt;td&gt;Norwalk CT 06851&lt;/td&gt;
          &lt;/tr&gt;
          &lt;tr&gt;
              &lt;td&gt;&lt;/td&gt;
              &lt;td&gt;Tel&lt;/td&gt;
              &lt;td&gt;Main&lt;/td&gt;
              &lt;td&gt;Slough SL1 4DX&lt;/td&gt;
          &lt;/tr&gt;
          &lt;tr&gt;
              &lt;td&gt;&lt;/td&gt;
              &lt;td&gt;Tel&lt;/td&gt;
              &lt;td&gt;Other&lt;/td&gt;
              &lt;td&gt;London W1B 5HQ&lt;/td&gt;
          &lt;/tr&gt;
      &lt;/tbody&gt;
  &lt;/table&gt;
  </code></pre>