new files: boost/detail/numeric_traits.hpp, libs/utility/numeric_traits_test.cpp

From: David Abrahams (abrahams_at_[hidden])
Date: 2001-01-21 23:26:12

numeric_traits.hpp -- so far, supplies a way to get the difference between
two integers with less likelihood of overflow/underflow. For more detail,
see the header comment.

Howard, I took the liberty of putting your name on the copyright notice for
is_signed<>, which stole from you. I liked your implementation better than
the one I was using ;-)

numeric_traits_test.cpp also has an example of recursive templates which
even work under MSVC. These templates statically compute the maximum and
minimum value of any built-in integral type.

-Dave

P.S. This is all part of the post-review work I'm doing on
iterator_adaptors.