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

gio/tests/gdbus-daemon.c

@@ -22,8 +22,6 @@ main (int argc, char *argv[])
     { NULL }
   };
 
-  g_type_init ();
-
   context = g_option_context_new ("");
   g_option_context_set_translation_domain (context, GETTEXT_PACKAGE);
   g_option_context_set_summary (context,