New method, to return an end-user-friendly name corresponding to a

New method, to return an end-user-friendly name corresponding to a

	* camel-service.c (camel_service_get_name): New method, to return
	an end-user-friendly name corresponding to a service. (eg, "POP
	service for danw on trna.helixcode.com").

	* providers/imap/camel-imap-store.c,
	providers/mbox/camel-mbox-store.c,
	providers/nntp/camel-nntp-store.c,
	providers/pop3/camel-pop3-store.c,
	providers/sendmail/camel-sendmail-transport.c,
	providers/smtp/camel-smtp-transport.c: Implement.