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/filter-cat.c

@@ -215,8 +215,6 @@ main (int argc, char *argv[])
   GFile *file;
   int i;
 
-  g_type_init ();
-
   context =
     g_option_context_new ("LOCATION... - concatenate LOCATIONS "
 			  "to standard output.");