refactor($ionicScrollDelegate): make it a factory from current scope

BREAKING CHANGE: $ionicScrollDelegate no longer works globally; you must
create a new instance of each time you use it.  The actual methods on
each instance of $ionicScrollDelegate are the same, however.

Change your code from this:

```js
function MyController($scope, $ionicScrollDelegate) {
  $scope.scrollTop = function() {
    $ionicScrollDelegate.scrollTop();
  };
}
```

To this:

```js
function MyController($scope, $ionicScrollDelegate) {
  var delegate = $ionicScrollDelegate($scope);
  $scope.scrollTop = function() {
    delegate.scrollTop();
  };
}
```
test(sideMenu2): update test to reflect changes