E-Mail as Username

Use the user's email address as the username!

This module enables the use of email addresses as the Drupal account username.
The following things are changed / added:

• The name user field is not required anymore
• The mail user field is now required
• The mail user field is more thoroughly validated
• The name user field is set to the value of the mail field on presave.
• Existing users have their name set to the mail field value if they have an email set.
• Configurable validation of email DNS settings and spoofing (requires intl PHP extension)