title: ngChange not Triggered on ngModel change
body: <p>UI bootstrap demonstrates a select dropdown using a button and a unordered list.  This is all fine and dandy, however, I am trying to get the same functionality as a select tag in HTML.  Functionality like selecting an option and changing the value of the model then firing a ng-change function. </p>
  
  <p>I thought that an ngChange event fires when the ngModel attached to the input changes, however, this is not the case.  I have attached a plunker with my problem, which demonstrates the selection of the list item that changes the <code>user.group</code>'s <code>ng-model</code>, which should call the <code>ng-change="alert('blah')"</code>, but it doesnt.  Am I missing some kind of semantics with ngChange?</p>
  
  <p><a href="http://plnkr.co/edit/oZo7xGEVKvB0ntwiNFMp?p=info" rel="nofollow">http://plnkr.co/edit/oZo7xGEVKvB0ntwiNFMp?p=info</a></p>