created feedback loop from between sequence block models and the course repo via change event listeners. courses will be checked back into the repo on unassignment from the sequence block.
added getter method for the application's status bar to allow for lazy initialization.
bugfix: fixed regression that was invoking the wrong method in the datasource from being invoked when the delete report button is clicked.
added getter method for application's data source property.
cleanup: removed obsolete "sequence" entity from the controller and client-side app, there will be no controls for any of its properties in the UI.