Update callers

Adapt all our tests and examples to the new initialization api.

tests/motion-compression.c

@@ -43,7 +43,7 @@ main (int argc, char **argv)
   GtkWidget *scale;
   GtkWidget *da;
 
-  gtk_init (&argc, &argv);
+  gtk_init ();
 
   window = gtk_window_new (GTK_WINDOW_TOPLEVEL);
   gtk_window_set_default_size (GTK_WINDOW (window), 300, 300);