Merging minor tested bugfixes from trunk.

svn path=/branches/release/boost/exception/; revision=77592
Merged changes from trunk: dealing with warnings, and a compile error on Win CE.

svn path=/branches/release/boost/exception/; revision=79026
Merging long-standing changes from Trunk, including the slightly more sophisticated handling of the to_string conversion done in boost::diagnostic_information.

svn path=/branches/release/boost/exception/; revision=83354