V2.2 regions normalize ui

New branch for issue #1649

Adds support for @ui.syntax selectors in regions hash.

For example:

```
var layoutView = Backbone.Marionette.LayoutView.extend({
    regions: {
        foo: '@ui.bar'
    },
    ui: {
        bar: '.baz'
    }
});
```
The deep compare feels like a broader test of region instantiation methods. I think you were right with the original suggestion to just drop the redundant `to.exist` and use the `to.equal`.

Really with this test I just wanted to check that the region still instantiated and that the UI class was used.