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'
    }
});
```
I'm not 100% sure what you mean - are you talking about splitting this up into two functions one for normalizing keys one for normalizing values?

No problem by the way, I've been using Marionette pretty much every day for the last year and a half so about time I contributed something!