title: Tree Selection SAPUI5 (with checkboxes). Auto check child nodes when parent node is checked
body: <p>I have a Tree element with MultiSelect mode, which looks good with checkboxes in every tree item. I wanted to make it so if I select one item, all of its children get selected as well. I have the tree in the view: </p>
  
  <pre><code> &lt;Tree selectionChange="onPress" itemPress="onPress" includeItemInSelection="true" mode="MultiSelect" items="{path: '/'}" id="Tree"&gt;
      &lt;headerToolbar&gt; 
         &lt;Toolbar&gt; 
            &lt;content&gt; 
               &lt;Title level="H2" text="Title"/&gt; 
               &lt;ToolbarSpacer/&gt; 
            &lt;/content&gt; 
         &lt;/Toolbar&gt;
      &lt;/headerToolbar&gt;
      &lt;StandardTreeItem title="{text}"/&gt;
   &lt;/Tree&gt;
  </code></pre>
  
  <p>I wanted to know if SAPUI5 had a property for its trees like "Check Children" or something similar. And if not, how could I do it.</p>
  
  <p>Thanks.</p>