Improves email validation in the following ways:
More extensive typo detection
Checks the domain-part of an email is "valid" and can receive email (ie has an MX/A record), and then checks any MX records are not listed in the banned email domain list
This validation is done via the bundled version of GitHub - egulias/EmailValidator: PHP Email address validator
Provides a "Test email address validity" (/admin.php?tools/test-email-address-validity) Page to give in-depth reporting of why an...
