Integrate webform email resend feature with email confirmations

Fixes three issues:

1. Webform's "resend" feature for submission notifications did not work with email wrappers enabled.

2. $message['send'] = FALSE in email_wrappers_mail_alter caused
Improper error message to appear to site admins on resend after issue#1 was fixed.
We need to unset webform's resend submit function in order to check 
whether an email has a wrapper, and recompose the messages.

2. $account = $user in email_wrappers_mail_alter is wrong value for resends.