Merge unordered from trunk.

Add `BOOST_NOEXPECT` to:

- Move constructors (when appropriate)
- Destructors
- Iterators

Also, fix some misleading documentation about the containers' move support.


[SVN r85048]

test/unordered/Jamfile.v2

@@ -25,6 +25,7 @@ test-suite unordered
         [ run minimal_allocator.cpp ]
         [ run compile_set.cpp ]
         [ run compile_map.cpp ]
+        [ run noexcept_tests.cpp ]
         [ run link_test_1.cpp link_test_2.cpp ]
         [ run incomplete_test.cpp ]
         [ run simple_tests.cpp ]