added unwrap member function.
Added move semantics from this to unwrap.
Fix typo.
Added void_t.
Cleanup.
Mkae value_traits SFINAE friendly. fixes #34?
Added valued::value_or generic algorithm.
 Make valued a requirement of errored - fix #39.
fix typo.
remove dependency on pointer_like.
Added Rebindable concept and make Valued refine rebindable.
make use of rebindable::value_type<E> where possible.
Merge branch 'viboes_interface_change'

Conflicts:
	test/jamfile.v2