Add support for GArrays: add g_type_info_get_array_type() and properly scan GArray args

Based on a previous patch by C. Scott Ananian <cscott@litl.com>

https://bugzilla.gnome.org/show_bug.cgi?id=581687

girnode.c

@@ -1497,6 +1497,7 @@ g_ir_node_build_typelib (GIrNode         *node,
 		      array->zero_terminated = type->zero_terminated;
 		      array->has_length = type->has_length;
                       array->has_size = type->has_size;
+                      array->array_type = type->array_type;
 		      array->reserved2 = 0;
                       if (array->has_length)
                         array->dimensions.length = type->length;