Migrate to PHPMailer

[artfulbodger]

Migrate away form mail() which will add the following improvements

• Custom SMTP

• DKIM signed emails

[artfulbodger]

• [x] accountCheck.php
• [x] addAfterClose.php
• [x] addMembers.php
• [x] change.php
• [x] createAccount.php
• [x] group_registrations.php
• [x] individual.php
• [x] leader_registrations.php
• [x] participant_registrations.php
• [ ] recPay.php
• [x] registrationsLeaders.php
• [x] registrationsParticipants.php
• [x] registrationsStaff.php
• [ ] resendVerification.php
• [x] staffReg.php