tuple (__add_c_ref, [...]): Remove.

tuple (__add_c_ref, [...]): Remove.

	* include/std/tuple (__add_c_ref, __add_ref, __add_r_ref): Remove.
	(__tuple_element_t): Define.
	(tuple_element): Use __tuple_element_t.
	(__cv_tuple_size): Define.
	(tuple_size<cv _Tp>): Use __cv_tuple_size.
	(get, __get_helper, __get_helper2): Remove uses of __add_ref etc.
	(get<_Tp>(tuple<_Types...>&&)): Use forward instead of move.
	(__tuple_compare): Remove size check, re-order parameters.
	(operator==, operator<): Use static_assert to check requirements.
	* include/std/functional (__volget): use __tuple_element_t.
	* testsuite/20_util/tuple/element_access/get_by_type.cc: Test rvalues.
	* testsuite/20_util/uses_allocator/cons_neg.cc: Adjust dg-error.

From-SVN: r210447