The Notification plugin provides various ways to notify the user
of new and possibly unread mail. Currently, the following modules
are implemented:

	* A mail banner (stocks ticker-like widget)
	* A popup window
	* A command to be issued on new mail arrival

All modules can be activated or deactivated at compilation time,
and are highly configurable at run time. It is possible to include
only selected folders in any module.  In general, the notification
is executed after filtering, so it is possible to exclude spam or
other unwanted messages from notification.