Illustrates:
Separation of concerns, SRP, MVC
BlobGui.java launches system.
Uses a list to implement 1-many.
Exactly the same as design_example_map except that BlobManager.java uses a map

Uses MVC approach where controller manipulates model and updates the view.
Doesn't have packages for Model, View, and Controller. If it did, the View class
(BlobGui) would need to define update methods, or getters for the controls, or
make the controls public. Not sure what the best approach is.
Also, controller has a bit of logic in addBlob, which could be farmed out to a 
new class (or existing?).

