type_traits: Implement is_same, add_reference and remove_reference.

2004-12-08  Paolo Carlini  <pcarlini@suse.de>

	* include/tr1/type_traits: Implement is_same, add_reference and
	remove_reference.
	* testsuite/testsuite_tr1.h (test_relationship): New.
	* testsuite/tr1/4_metaprogramming/reference_modifications/
	add_reference.cc: New.
	* testsuite/tr1/4_metaprogramming/reference_modifications/
	remove_reference.cc: Likewise.
	* testsuite/tr1/4_metaprogramming/relationships_between_types/
	is_same/is_same.cc: Likewise.
	* testsuite/tr1/4_metaprogramming/relationships_between_types/
	is_same/typedefs.cc: Likewise.

	* testsuite/tr1/4_metaprogramming/type_properties/is_const/
	is_const.cc: Minor tweaks.
	* testsuite/tr1/4_metaprogramming/type_properties/is_volatile/
	is_volatile.cc: Likewise.

From-SVN: r91907