Changes

Creates EJBs to handle email and user registration
Creates simple User entity(to be modified later). Creates EJB
RegisterEJB to handle the registration of an user, as well as the
confirmation of the registration. Creates EJB MailerEJB to handle the
sending of the registration email. Creates test class RegisterEJBTest to
test EJB Creates stub MailerStub for testing purposes.

Renames RegisterEJBTEst.java to RegisterEJBTest.java