[boost] function_traits class template added to type_traits library

From: Douglas Gregor (gregod_at_[hidden])
Date: 2002-08-04 22:11:48

I've added a function_traits class template to extract the arity, return type, 
and argument types from a function type. It's only available when partial 
specialization is available, although we can extract the arity in the absence 
of partial specialization if anyone is interested. Testcases & docs also in 
CVS. 

boost::function is using this now.

        Doug