processQueue = function( model ) {
					if ( model === dit ) {
						dit._deferProcessing = false;
						dit.processQueue();
						collection.off( 'relational:add', processQueue );
					}
				}
A type of Backbone.Model that also maintains relations to other models and collections.
New events when compared to the original:
 - 'add:<key>' (model, related collection, options)
 - 'remove:<key>' (model, related collection, options)
 - 'change:<key>' (model, related model or collection, options)