window: Set ALL_EVENT_MASK

This is a trivial commit that does a big change: We now ignore event masks.

Further commits will clean up code, but if bisection ends up here, you
know it's because code is getting delivered events that it weren't getting
before.

gdk/gdkwindow.c

@@ -939,7 +939,7 @@ gdk_window_new (GdkDisplay    *display,
       return NULL;
     }
 
-  window->event_mask = attributes->event_mask;
+  window->event_mask = attributes->event_mask | GDK_ALL_EVENTS_MASK;
 
   if (attributes->wclass == GDK_INPUT_OUTPUT)
     {