Return an array with all records presented in the tree.
Examples
sample
<button onclick="alert(JSON.stringify(tree.getAll()))" class="gj-button-md">Get All Data</button>
<button onclick="tree.addNode({ text: 'New Node' });" class="gj-button-md">Add New Node</button>
<br/>
<div id="tree"></div>
<script>
var tree = $('#tree').tree({
dataSource: [ { text: 'foo', children: [ { text: 'bar' } ] } ]
});
</script>