This class implements an email auto-response system. It accesses mailboxes via POP3 or IMAP protocols and sends out automatic responses emails to the messages foun in the inbox folder. Currently it implements three types of auto-response: * Send a response message using a given file * Send response message using contents read from a given Web URL (in this case the email subject has the URL request) * Send a custom response message generated by the current script The response messages may be in plain text or HTML. After the auto-response is sent, the mails are marked read or can be deleted. This class is meant to be used from tasks run periodically for instance as cron jobs.