Assignment2

Submission for assignment 2 is included in this "Assignment2" branch.  I used mock (EasyMock) SubscriptionPeriod objects in my SubscriptionTest class.  Beyond that, I added equals, hashCode, toString, clone, and compareTo methods to the SubscriptionPeriod class - would have done the same to the Subscription class but ran out of time.  Had to go back and add additional mock SubscriptionPeriod objects to the SubscriptionTest class after I refactored the Subscription class to make use of the SubscriptionPeriod class' clone method.
Kept finding myself wanted to implement a partial mock so I could pass arguments to the contructor of the object being mocked but kept slapping myself on the back of the hand, as Mr. Beck would say.