Use g_timeout_add_seconds() for power efficiency

This attempts to align second-granularity wakeups across the system,
reducing CPU wakeups a little.

I considered all timeouts of duration 1 second or greater, and moved
the non-timing-critical ones to g_timeout_add_seconds(). (Actually,
I didn't find any that I felt were timing-critical)

src/sugar/graphics/alert.py

@@ -376,7 +376,7 @@ class TimeoutAlert(Alert):
         canvas.show()                       
         self.add_button(gtk.RESPONSE_OK, _('Continue'), canvas)
 
-        gobject.timeout_add(1000, self.__timeout)
+        gobject.timeout_add_seconds(1, self.__timeout)
         
     def __timeout(self):
         self._timeout -= 1