everything: use libgudev instead of HAL; merge NM and nm-system-settings

The only thing that doesn't work yet is the system-settings service's
"auto eth" connections for ethernet devices that don't have an existing
connection.  Might also have issues with unmanaged devices that can't
provide a MAC address until they are brought up, but we'll see.

src/NetworkManagerUtils.h

@@ -46,6 +46,8 @@ void nm_utils_call_dispatcher (const char *action,
                                NMDevice *device,
                                const char *vpn_iface);
 
+gboolean nm_match_spec_hwaddr (const GSList *specs, const char *hwaddr);
+
 
 GHashTable *value_hash_create          (void);
 void        value_hash_add             (GHashTable *hash,