Implement 'Views object should accept functions that return a View', #366

Added a few simple lines to `setupView` that will invoke any functions passed in the `views` object attached to a View. I removed the call to `setupView` in the Backbone.Layout constructor; it was being called both there and again inside `_configure`. This was causing problems with this patch. The test case requires Backbone.View._configure to run so that `this.collection` is bound; with `setupView` in the constructor, it ran too early.

Removing the call and simply setting `manage = true` so that `setupView` is called in `_configure` fixed the issue and did not break any other tests.