public void dispose() {
		// stop all mutations and animations
		jobRunner.dispose();
	}
Add a listener to be notified when a job is started.  Jobs often, but not always, mutate
the underlying graph.  For this reason, other tasks that use the graph may want to not 
do their work while a job is running. 

@param c the listener
Ghidra/Framework/Graph/src/main/java/ghidra/graph/viewer/VisualGraphViewUpdater.java