### Added
- Add IMAP Authentication Plugin which stores the IMAP server to a DB field and handles the registration and authentication of IMAP users.
### Changed
- Add extra plugin hooks `beforeVerifyUser` & `afterVerifyUser` in `60.plugins.php`.
- Change the `login.class.php` by calling the `beforeVerifyUser` & `afterVerifyUser` hooks in order to support more authentication methods.