[boost] promote "unwrap" to ref.hpp

From: Ronald Garcia (garcia_at_[hidden])
Date: 2008-05-16 15:56:58

Hi all,

boost::reference_wrapper exists at the top-level of boost (in boost/ 
ref.hpp), but that header provides no way to unwrap a  
reference_wrapper.  There are two implementations floating around of  
"unwrap", one in boost.bind's implementation details, and one in  
boost.mpl's implementation details.  Is there any problem with  
providing a version of unwrap in ref.hpp?

ron