[boost] [config] BOOST_NO_RTTI patch for the release branch

Please someone take a look at this patch for boost/config for the release branch, which merges the recently added BOOST_NO_RTTI support from trunk, and commit it if everything is OK. Thanks, Emil Dotchevski Reverge Studios, Inc. http://www.revergestudios.com/reblog/index.php?n=ReCode