Bring getRegionManager and region options on Application in line with LayoutView

This PR should satisfy #1485 if I interpreted it correctly.  I read through #1516 but didn't see a dev branch yet, so I based off master.  Please let me know if I need to change.
Could you make this quick change:
```diff
  getRegionManager: function() {
-   suite.spy.apply(this, arguments);
    return new Marionette.RegionManager();
```
```js
this.sinon.spy(this.App.prototype, 'getRegionManager');
```