region._ensureViewIsIntact

Having the region check for view.isDestroyed does two things:

1. It allows you to handle the error of a region.show without the region killing the currentView and breaking without recourse.

2. appending isDestroyed to a Backbone.View on region empty adds the same safety for not re-showing a removed backbone view.
Improves Application triggerMethod arguments.
Update param types for addRegion method
Removes unnecessary emptyRegions call in LayoutView.
Updates file names; remove unnecessary files.
Update region-manager.jsdoc
Uses on instead of listenTo for the view show callback.
Improve undefined region show message.

Fixes #1913
adding item-view.jsdoc... again
Add auto addRegions behavior to regionMananger

fixes #1902
fix indentation for destroy method for proper JSON output :neckbeard:
Aliases Marionette as Mn
Updates Module documentation.
Updates Controller documentation.
Replaces slice with _.toArray
Updates docs to use getter methods.
Adds isNodeAttached helper method.
Adds _getNestedView to Layout and Collection Views.
Refactor Application to subclass Object
Refactor Behavior to subclass Object