Remove g_type_init() calls

Very many testcases, some GLib tools (resource compiler, etc) and
GApplication were calling g_type_init().

Remove those uses, as they are no longer required.

https://bugzilla.gnome.org/show_bug.cgi?id=686161

tests/gobject/performance-threaded.c

@@ -340,8 +340,6 @@ main (int   argc,
   GError *error = NULL;
   int i;
 
-  g_type_init ();
-
   context = g_option_context_new ("GObject performance tests");
   g_option_context_add_main_entries (context, cmd_entries, NULL);
   if (!g_option_context_parse (context, &argc, &argv, &error))