merged changes from branches/iostreams_dev, revisions 42565-42595:
- Simplified implementation with the help to the C-runtime function _get_osfhandle so that on Windows only a single HANDLE is stored and the POSIX-style implementation is never needed; added the handle_type on POSIX systems (typedef for int) and a function returning the underlying handle as an instance of handle_type
- fixed the bug described in ticket Ticket #1551 (stream_buffer::seekpos ignores openmode parameter)
- fixed test/operation_sequence_test.cpp file description
[SVN r42596]
Jonathan Turkanis