support for exception_ptr and nesting in boost::diagnostic_information

documentation update

[SVN r53038]

libs/exception

@@ -1 +1 @@
-Subproject commit 15c0ff6130f5e2b2300302f2494ee42562ce5660
+Subproject commit 1643ad2e81e656ccb992b132c42a1472b72e6c83