title: How to use Ext.ComponentQuery.query with nested attributes
body: <p>How to use Ext.ComponentQuery.query with nested attributes in Sencha Touch?</p>
  
  <p>e.g </p>
  
  <pre><code>var myHardtoGetObj = topLevelView.down('someview[config.categoryCfg.id=1]')[0];
  </code></pre>
  
  <p>This gets me "uncaught error"</p>
  
  <p>given : </p>
  
  <pre><code>Ext.define('SomeView', {
      xtype : 'someview',
      config : {
          categoryCfg : {
              id   : 5,
              name : 'someName' 
          }
      }
  });
  </code></pre>
  
  <p>Is this possible?</p>
  
  <p>Thanks.</p>