Unconfirmed Addresses Block Registration

Right now if a user attempts to register with an email address that another user has added to their email addresses but has not yet confirmed, the new user's registration is blocked. This behavior must be changed to one of the following:

1. Cancel the pending confirmation and allocate the email address to the new user
2. Take new registrant to another page confirming that they actually wish to register a new account, then proceed with item #1 above