Case of Emails should be properly handled

As per RFC 2821
The local-part of a mailbox MUST BE treated as case sensitive. Therefore, SMTP implementations MUST take care to preserve the case of mailbox local-parts. Mailbox domains are not case sensitive. In particular, for some hosts the user "smith" is different from the user "Smith".

Moodle should handle email in a similar way, i.e the domain part (after @) should be case-insensitive and local part (before @) should be case-sensitive. At present Moodle uses simple "=" matches for emails in most location which needs to be updated to use above mentioned format.