Email Change login/confirmation lockout.

[chalupagrande]

Currently, when the user goes to change their email, they could potentially be locked out, should they not confirm their new email.

The experience could be:

1. If the user changes their email, they should still be able to login using their old email, until they confirm their new email address.
2. The user changes their email, and is not logged out. They can still login using their old email until they confirm their email.
3. The concept of primary email - their current email stays their mail login, until they confirm and change their email. This new email becomes their primary and any other email is saved as an alternate email.