A test driver for Item

• It is much simpler than InventoryTests.java but that is a good example
• Consider one test method for the constructors and accessors and toString
• Consider another test method for the mutators
• Consider another test method for the equals and compareTo. There should be a total of at least 7 calls (two for each of the equals <true, false>, and three for the compareTo [<, ==, >])