* Bad smell: AcmeVendingMachine had GUI code in it. Plan will be to move all UI code into the GUI class and expose interfaces from the AcmeVendingMachine class.

* Bad smell: AcmeVendingMachine was tightly coupled with reading input from a text file. This will be fixed by reading in the text file in the Main class and adding those strings into the AcmeVendingMachine class.