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/gio-querymodules.c

@@ -129,8 +129,6 @@ main (gint   argc,
 {
   int i;
 
-  g_type_init ();
-
   if (argc == 1)
     {
       g_print ("Usage: gio-querymodules <directory1> [<directory2> ...]\n");