Added SandwichOrderData class to represent the sandwich order as it is built.  This is in preparation for adding pricing logic to calculate total price.  Added JUnit test for SandwichOrderData class.  Added JavaDoc comments for the classes in Model package.  Updated the SummaryPane class with a new setDisplayArea method that accepts the String representation of an order.  This is in addition to the existing setDisplayArea method that accepts a List of Strings.  Updated MainFrame class runSummary method to build the SandwichOrderData object instead of the ArrayList of strings -  left the commented out calls for now so you can see the difference.  This is to prepare for calculating the price and setting it in the SandwichOrderData object instance. Called the new setDisplayArea method for the Summary Pane.