Updated establishFriendship(), initiateFriendship(), threeDegrees()
Updated establishFriendship(), initiateFriendship(), threeDegrees()

- establishFriendship() and initiateFriendship() methods have an
	added check to make sure the user doesn't friend themselves.

- threeDegrees() method changed the input to retrieve an email
address instead of firstname/lastname because the email field is unique
within the Users table.

outkst/CS1555TermProject