Added NOTIFICATION_STORAGE_MAILER which allow to store the email in a storage (could be just output, file, database ...)
Added SMTP implementation, based on EiffelNet SMTP_PROTOCOL.
note: it is possible to exclude this by setting ecf variable "smtp_notification_email_disabled" to "True"
this way help to manage dependencies, since the Eiffel Net library would not be included neither.
Fixed Date header value computation.
