Map the username to the email of the user

When the admin is using the GP found in TRUNK-3651, the user should not have to put in their email as their username and then their email in the Notifications section of My Profile. This way we avoid the user having to do double entry of their email.

On saving the user or saving the profile, the username and the email user_property should be matched up.

See the OptionsFormController class and the UserServiceImpl.saveUser method.