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/refcount/objects2.c

@@ -103,7 +103,6 @@ main (int argc, char **argv)
 
   g_print ("START: %s\n", argv[0]);
   g_log_set_always_fatal (G_LOG_LEVEL_WARNING | G_LOG_LEVEL_CRITICAL | g_log_set_always_fatal (G_LOG_FATAL_MASK));
-  g_type_init ();
 
   test = g_object_new (G_TYPE_TEST, NULL);