title: Ext JS 4 using JSON in proxy reader will not load records
body: <p>I am trying to use Ext JS 4 and was playing with one of the grid examples and wanted to use JSON rather than XML. No mater how I code the JSON data, I get no records to load.</p>
  
  <p>Here is my code:</p>
  
  <pre><code>Ext.define('Plant', {
      extend: 'Ext.data.Model',
      fields: [{
          name: 'common',
          type: 'string'
      }, {
          name: 'botanical',
          type: 'string'
      }, {
          name: 'light'
      }, ]
  });
  
  // Create the Data Store.
  var store = Ext.create('Ext.data.Store', {
      // Destroy the store if the grid is destroyed.
      autoDestroy: true,
      model: 'Plant',
      proxy: {
          type: 'ajax',
          url: 'plants.json',
          reader: {
              type: 'json',
              root: 'records'
          }
      },
      sorters: [{
          property: 'common',
          direction: 'ASC'
      }]
  });
  </code></pre>
  
  <p>Here is my data:</p>
  
  <pre><code>{
      "records": [
          {
              "common":    "Bloodroot",
              "botanical": "Sanguinaria canadensis",
              "light":     "Mostly Shady"
          }, {
              "common":    "test",
              "botanical": "I do not know",
              "light":     "Mostly Shady"
          }
      ]
  }
  </code></pre>
  
  <p>The XML reader works great, but we want to use JSON. </p>
  
  <p>Thanks in advance</p>