Update App to support lazy container creation. Also moved CSS class stamping to render-time instead of init time.

Destroying a view no longer destroys that view's container. [Ticket #2531689] Pass {remove: true} to the view's destroy() method to destroy the container as well. This change required a few changes to Y.App to maintain its expected behavior.

Y.App now looks up "Deeply.Namespaced.Views". Fixes #2531736. This now works: new Y.App({ views: { foo: {type: 'MyApp.Views.Foo'} } });

Added more Y.App unit tests to increase coverage to maximum.

Updated App's `showView()` test to handle new `options` signature. The options mixed onto the `activeViewChange` event facade are now all added under the `e.options` property.

Y.App no longer messes with other's objects when creating its `views`. Extra steps are now taken to merge together default view-related metadata from the `views` object on the prototype with the specified `config.views` object such that the resulting merged set of metadata does not affect anyone's own objects. Unit tests which depended on the old merging behavior have been updated.

Unit tests for Y.App, tons of 'em! These passed the tests in all the browsers I have, expect Amazon Silk on the Kindle Fire when in Desktop mode; that will be fixed with a UA entry update.