Widgets with assigned IDs should be added to a "widgets" object

[patrick-steele-idem]

Template:

<div w:widget="demo/ParentWidget">
  <ui:button label="Delete" w:id="deleteButton"/>
</div>

OLD demo/ParentWidget.js:

this.deleteButton.doSomething();

NEW demo/ParentWidget.js:

this.widgets.deleteButton.doSomething();