Fraction implements Serializable. 
  Write a test that serializes and deserializes a Fraction object; That is:
Create a Fraction
Create a ByteArrayOutputStream
Chain an ObjectOutputStream to the ByteArrayOutputStream
Write the Fraction object onto the ObjectOutputStream using writeObject()
Close the ObjectOutputStream
Get a byte array from the ByteArrayOutputStream using toByteArray()
Make a ByteArrayInputStream from the byte array
Chain an ObjectInputStream to the ByteArrayInputStream
Read the object from the ObjectInputStream using readObject()
Verify that the object is equal to but not the same as the original object