New MailScanner Front-End (MSFE) v4.0

Changes:

• Installation no longer attempts to recreate mailscanner database or update the MailScanner configuration settings if the mailscanner MySQL database already exists
• Added whitelisting to virus.scanning.rules for mails released from quarantine (i.e. sent locally and from the postmaster@hostname address)
• Moved to a simpler installer script using the license server
• Timeout version checks incase version server is unavailable
• Added check for incorrect ClamAV (or clamavconnector) installation which causes MailScanner to be disabled
• Improved support for remote MySQL database servers