[boost] Attn: users of minimal.hpp and boost/test/included headers

Hi, Those of you who use minmial.hpp have to add boost/test/minimal in requirements section of Jamfile. Those who are using included variant of the UTF should add boost/test/included. This is nessesary to enable async exceptions for msvc toolset. Otherwise some of the Boost.Test functionality may not work as expected, especially with msvc 8.0. Gennadiy