Adds helper methods to AppRouter.
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.

The extra return this; was removed to prevent jslint error for too many statements, and seemed unnecessary
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
Update param types for addRegion method
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.