Merge utility documentation.

- Fixed duplicate anchors.
- Add BOOST_EXPLICIT_OPERATOR_BOOL documentation.
- Rebuild some of the utility documentation.


[SVN r86797]

libs/utility

@@ -1 +1 @@
-Subproject commit 44a98b121b052f722b971a1d19531d1be7e83bff
+Subproject commit 96da5105ab5b7203a6ef08c9a63b8f523fc8db5e