Remove syncpipe pkg

This removes the entire syncpipe package and replaces it with standard
operations on the pipes.  The syncpipe type just never felt right and
probably should not have been there.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
And here was my question about difference between `socketpair` and `pipe2`. Can't we use just `os.Pipe` here?