tor/changes/UserspaceIOCPBuffers

  o Minor features:
    - Experimental support for running on Windows with IOCP and no
      kernel-space socket buffers. This feature is controlled by a new
      UserspaceIOCPBuffers feature (off by default), which has no
      effect unless Tor has been built with support for bufferevents,
      is running on Windows, and has enabled IOCP.  This may, in the
      long run, help solve or mitigate bug 98.