title: Binding imperatively
body: <p>Is there a way to set up bindings imperatively. An example use case:</p>
  
  <pre><code>var el2 = new MyElement();
  el2.myProp = this.$.anotherElement.anotherProp
  </code></pre>
  
  <p>That won't setup a binding, it just assigns the value or object. I'd like to find a way to do something like:</p>
  
  <pre><code>el2.myProp.bindTo(this.$.anotherElement.anotherProp)
  </code></pre>
  
  <p>Possible?</p>