Windows now matches other platforms in that a child calling exit(N) causes
result() to return N and full_result() to return N << 8. On Windows, before
this change, result() was returning N >> 8, and full_result() was returning N.
Programs having workarounds for this may need to condition those workarounds on
$IPC::Run::VERSION.

• #157 - On Windows, avoid hang under IPCRUNDEBUG.
  
• Refresh "cpanfile" from Makefile.PL, to allow use on Windows.
  
• #163 - Normalize shebangs to /usr/bin/perl
  
• Fix or skip all tests recently seen to fail on Windows.
  
• Include t/result.t in releases.
  
• #168 - Make full_result() and result() Windows behavior match non-Windows.