* include/std/tuple (_Index_tuple, _Build_index_tuple): Move to
	<utility>.
	* include/std/utility (integer_sequence, make_integer_sequence,
	index_sequence, make_index_sequence, index_sequence_for): Define.
	* doc/xml/manual/status_cxx2014.xml: Update.
	* testsuite/20_util/integer_sequence/intseq.cc: New.
	* testsuite/20_util/integer_sequence/requirements/typedefs.cc: New.

From-SVN: r204275