New TemporaryFile implementation for Windows: this doesn't need a

New TemporaryFile implementation for Windows:  this doesn't need a
TemproraryFileWrapper wrapper anymore, and should be immune from the
problem that a temp file inherited by a spawned process caused an
attempt to close the temp file in the spawning process to blow
up (the unlink in TemporaryFileWrapper.close() blew up with a
"Permission denied" error because, despite that the temp file got
closed in the spawning process, the spawned process still had it open
by virtue of C-level file descriptor inheritance).  In context,
that bug took days to figure out <wink/sigh>.