[Python-3000] os.popen versus subprocess.Popen

["Martin v. Löwis"]

> IMO os.popen() is wrong here.

Should os.popen go away entirely?

Apparently, it does two things:
a) redefine close to block until the child process terminated,
and
b) wrap stdout/stdout with a TextIOWrapper

If there is an actual need to specify an encoding when communicating
with the subprocess, I'd rather make that parameter to Popen itself.

Regards,
Martin