merged from trunk

svn path=/branches/proto/v4/boost/asio.hpp; revision=47983
merged from trunk

svn path=/branches/proto/v4/boost/asio/; revision=48062
merged from trunk

svn path=/branches/proto/v4/boost/asio.hpp; revision=48605
merged from trunk

svn path=/branches/proto/v4/boost/asio/; revision=48781
merged from trunk

svn path=/branches/proto/v4/boost/asio/; revision=49439
merged from trunk

svn path=/branches/proto/v4/boost/asio/; revision=49607