Regressions Fixed, AUS Idle Timer

Compiling: You can link against a local Cairo library again (Bug 368844) and DBUS is activated by default on Linux/UNIX now (Bug 388743), changing the available configure option switch from "--enable-dbus" to "--disable-dbus".

MailNews: The news://host/mid newsgroup post URI scheme is working again (Bug 404389).

General: The software update (AUS) dialog appears only after a idle timeout now (Bug 323041).