App Already Bootstrapped with this Element '{0}'
Occurs when calling angular.bootstrap on an element that has already been bootstrapped.
This usually happens when you accidentally use both ng-app and angular.bootstrap to bootstrap an
application.
<html>
...
<body ng-app="myApp">
<script>
angular.bootstrap(document.body, ['myApp']);
</script>
</body>
</html>
Note that for bootstrapping purposes, the <html> element is the same as document, so the following
will also throw an error.
<html>
...
<script>
angular.bootstrap(document, ['myApp']);
</script>
</html>
You can also get this error if you accidentally load AngularJS itself more than once.
<html ng-app>
<head>
<script src="angular.js"></script>
...
</head>
<body>
...
<script src="angular.js"></script>
</body>
</html>