Provide swappable traits (p0185r1)

Provide swappable traits (p0185r1)

2016-06-16  Daniel Kruegler  <daniel.kruegler@gmail.com>

	Provide swappable traits (p0185r1)
	* include/std/type_traits (is_swappable, is_nothrow_swappable,
	is_swappable_with, is_nothrow_swappable_with, is_swappable_v,
	is_nothrow_swappable_v, is_swappable_with_v,
	is_nothrow_swappable_with_v): New.
	* include/bits/stl_pair.h: Use it as per p0185r1.
	* include/bits/stl_queue.h: Likewise.
	* include/bits/stl_stack.h: Likewise.
	* include/bits/unique_ptr.h: Likewise.
	* include/std/tuple: Likewise.
	* include/std/array: Likewise. Fix zero-size member swap.
	* include/bits/hashtable.h: Use __and_.
	* testsuite/20_util/is_nothrow_swappable/requirements/
	explicit_instantiation.cc: Change test options to std=gnu++17.
	* testsuite/20_util/is_nothrow_swappable/requirements/typedefs.cc:
	Likewise.
	* testsuite/20_util/is_nothrow_swappable/value.cc: Likewise.
	* testsuite/20_util/is_swappable/requirements/
	explicit_instantiation.cc: Likewise.
	* testsuite/20_util/is_swappable/requirements/typedefs.cc: Likewise.
	* testsuite/20_util/is_swappable/value.cc: Likewise.
	* testsuite/20_util/is_nothrow_swappable/requirements/
	explicit_instantiation_ext.cc: New.
	* testsuite/20_util/is_nothrow_swappable/requirements/typedefs_ext.cc:
	New.
	* testsuite/20_util/is_nothrow_swappable/value.h: New.
	* testsuite/20_util/is_nothrow_swappable/value_ext.cc: New.
	* testsuite/20_util/is_nothrow_swappable_with/requirements/
	explicit_instantiation.cc: New.
	* testsuite/20_util/is_nothrow_swappable_with/requirements/typedefs.cc:
	New.
	* testsuite/20_util/is_nothrow_swappable_with/value.cc: New.
	* testsuite/20_util/is_swappable/requirements/
	explicit_instantiation_ext.cc: New.
	* testsuite/20_util/is_swappable/requirements/typedefs_ext.cc: New.
	* testsuite/20_util/is_swappable/value.h: New.
	* testsuite/20_util/is_swappable/value_ext.cc: New.
	* testsuite/20_util/is_swappable_with/requirements/
	explicit_instantiation.cc: New.
	* testsuite/20_util/is_swappable_with/requirements/typedefs.cc: New.
	* testsuite/20_util/is_swappable_with/value.cc: New.
	* testsuite/23_containers/array/tuple_interface/get_neg.cc: Adjust
	dg-error line numbers.
	* testsuite/23_containers/array/tuple_interface/tuple_element_neg.cc:
	Likewise.

From-SVN: r237531