improved code docs. further locked down the base model's clientid and id attribute by making them read-only.
implemented academic level model. updated code docs. added nulling out of the course attribute during sequence block deletion.
changed the format in which academic levels are delivered to the view from map to numeric array
further specified app properties and getter methods. improved code docs. started breakup up the app initialization into subroutines.
added input validation and exception handling to course repo object.
added academicLevel attribute to sequence block model.
added code to initialize sequence block models with academic year model objects on creation.