Boost Addressof Warning/Error under Intel C++ 13

Another quick post to provide a patch which fixes a warning in Boost.Utility/Addressof. This warning occurs under Intel C++ 13 (and probably other versions) when compiling at the highest warning level. Unlike other warnings though, it apparently cannot be disabled with #pragma directives, so if you compile with warnings as errors it results in an error which you cannot disable.

The root of the problem seems to be that the compiler thinks an rvalue is being passed to a function taking a non-const reference, however in this case it is a false positive (the rvalue has an implicit conversion operator which returns a reference to the underlying lvalue which it is wrapping). I have worked around it by turning the wrapper into an lvalue and passing that instead.