Implement observer_ptr.

Implement observer_ptr.

2015-05-01  Ville Voutilainen  <ville.voutilainen@gmail.com>

	Implement observer_ptr.
	* include/Makefile.am: Add new header.
	* include/Makefile.in: Regenerate.
	* include/experimental/memory: New.
	* testsuite/experimental/memory/observer_ptr/assignment/assign.cc: New.
	* testsuite/experimental/memory/observer_ptr/cons/cons.cc: New.
	* testsuite/experimental/memory/observer_ptr/hash/hash.cc: New.
	* testsuite/experimental/memory/observer_ptr/make_observer.cc: New.
	* testsuite/experimental/memory/observer_ptr/relops/relops.cc: New.
	* testsuite/experimental/memory/observer_ptr/requirements.cc: New.
	* testsuite/experimental/memory/observer_ptr/swap/swap.cc: New.
	* testsuite/experimental/memory/observer_ptr/typedefs.cc: New.

From-SVN: r222706