[boost] [1.47.0] Merge requests for iostreams + quickbook

Hi, Is it okay to merge a couple of changes to release? This change activates an existing workaround for Visual C++ 8 in iostreams. https://svn.boost.org/trac/boost/changeset/72726/ This change reverts the support for escaped characters in 'simple markup' in quickbook because it breaks the regex documentation. It isn't used anywhere else, and the documentation still builds, so it's safe. Will be reintroduced for quickbook 1.6. https://svn.boost.org/trac/boost/changeset/72695/